rake db:migrate 由于版本差异而中止答案

【问题标题】：rake db:migrate aborted due to version differencesrake db:migrate 由于版本差异而中止
【发布时间】：2014-04-24 08:24:07
【问题描述】：

我正在尝试在 localhost:3000 中加载我的 rails 应用程序，但是我遇到了一些与我的 rake 版本控制相关的错误。

当我使用 rails server 启动服务器然后在浏览器中刷新时，此错误会显示在我的服务器日志中：

ActiveRecord::PendingMigrationError - Migrations are pending; run 'bin/rake db:migrate RAILS_ENV=development' to resolve this issue.:
activerecord (4.0.4) lib/active_record/migration.rb:383:in `check_pending!'
activerecord (4.0.4) lib/active_record/migration.rb:370:in `call'
actionpack (4.0.4) lib/action_dispatch/middleware/callbacks.rb:29:in `block in call'
activesupport (4.0.4) lib/active_support/callbacks.rb:373:in `run__4154752559951713534__call__callbacks'
activesupport (4.0.4) lib/active_support/callbacks.rb:80:in `run_callbacks'
actionpack (4.0.4) lib/action_dispatch/middleware/callbacks.rb:27:in `call'
actionpack (4.0.4) lib/action_dispatch/middleware/reloader.rb:64:in `call'
actionpack (4.0.4) lib/action_dispatch/middleware/remote_ip.rb:76:in `call'
better_errors (1.1.0) lib/better_errors/middleware.rb:84:in `protected_app_call'
better_errors (1.1.0) lib/better_errors/middleware.rb:79:in `better_errors_call'
better_errors (1.1.0) lib/better_errors/middleware.rb:56:in `call'
actionpack (4.0.4) lib/action_dispatch/middleware/debug_exceptions.rb:17:in `call'
actionpack (4.0.4) lib/action_dispatch/middleware/show_exceptions.rb:30:in `call'
railties (4.0.4) lib/rails/rack/logger.rb:38:in `call_app'
railties (4.0.4) lib/rails/rack/logger.rb:20:in `block in call'
activesupport (4.0.4) lib/active_support/tagged_logging.rb:68:in `block in tagged'
activesupport (4.0.4) lib/active_support/tagged_logging.rb:26:in `tagged'
activesupport (4.0.4) lib/active_support/tagged_logging.rb:68:in `tagged'
railties (4.0.4) lib/rails/rack/logger.rb:20:in `call'
quiet_assets (1.0.2) lib/quiet_assets.rb:18:in `call_with_quiet_assets'
actionpack (4.0.4) lib/action_dispatch/middleware/request_id.rb:21:in `call'
rack (1.5.2) lib/rack/methodoverride.rb:21:in `call'
rack (1.5.2) lib/rack/runtime.rb:17:in `call'
activesupport (4.0.4) lib/active_support/cache/strategy/local_cache.rb:83:in `call'
rack (1.5.2) lib/rack/lock.rb:17:in `call'
actionpack (4.0.4) lib/action_dispatch/middleware/static.rb:64:in `call'
rack (1.5.2) lib/rack/sendfile.rb:112:in `call'
railties (4.0.4) lib/rails/engine.rb:511:in `call'
railties (4.0.4) lib/rails/application.rb:97:in `call'
rack (1.5.2) lib/rack/lock.rb:17:in `call'
rack (1.5.2) lib/rack/content_length.rb:14:in `call'
rack (1.5.2) lib/rack/handler/webrick.rb:60:in `service'
/Users/AaronWilliamson/.rubies/ruby-2.1.0/lib/ruby/2.1.0/webrick/httpserver.rb:138:in `service'
/Users/AaronWilliamson/.rubies/ruby-2.1.0/lib/ruby/2.1.0/webrick/httpserver.rb:94:in `run'
/Users/AaronWilliamson/.rubies/ruby-2.1.0/lib/ruby/2.1.0/webrick/server.rb:295:in `block in start_thread'

但是，当我按照错误的建议运行 bin/rake db:migrate RAILS_ENV=development 时，我收到以下错误：

Aarons-iMac:ripelist-classifieds AaronWilliamson$ bin/rake db:migrate RAILS_ENV=development
== 20140424074405 AddDeviseToUsers: migrating =================================
-- change_table(:users)
rake aborted!
StandardError: An error has occurred, this and all later migrations canceled:

PG::DuplicateColumn: ERROR:  column "email" of relation "users" already exists
: ALTER TABLE "users" ADD COLUMN "email" character varying(255) DEFAULT '' NOT NULL/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/postgresql/database_statements.rb:128:in `async_exec'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/postgresql/database_statements.rb:128:in `block in execute'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/abstract_adapter.rb:442:in `block in log'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activesupport-4.0.4/lib/active_support/notifications/instrumenter.rb:20:in `instrument'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/abstract_adapter.rb:437:in `log'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/postgresql/database_statements.rb:127:in `execute'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/abstract/schema_statements.rb:360:in `add_column'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/postgresql/schema_statements.rb:393:in `add_column'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/abstract/schema_definitions.rb:489:in `block (3 levels) in <class:Table>'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/abstract/schema_definitions.rb:488:in `each'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/abstract/schema_definitions.rb:488:in `block (2 levels) in <class:Table>'
/Users/AaronWilliamson/Ripelist-Classifieds/db/migrate/20140424074405_add_devise_to_users.rb:5:in `block in up'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/abstract/schema_statements.rb:334:in `change_table'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:629:in `block in method_missing'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:601:in `block in say_with_time'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:601:in `say_with_time'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:621:in `method_missing'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:387:in `method_missing'
/Users/AaronWilliamson/Ripelist-Classifieds/db/migrate/20140424074405_add_devise_to_users.rb:3:in `up'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:538:in `up'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:578:in `exec_migration'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:559:in `block (2 levels) in migrate'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:558:in `block in migrate'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:294:in `with_connection'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:557:in `migrate'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:713:in `migrate'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:963:in `block in execute_migration_in_transaction'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:1009:in `block in ddl_transaction'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/abstract/database_statements.rb:213:in `block in transaction'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/abstract/database_statements.rb:221:in `within_new_transaction'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/abstract/database_statements.rb:213:in `transaction'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/transactions.rb:209:in `transaction'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:1009:in `ddl_transaction'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:962:in `execute_migration_in_transaction'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:924:in `block in migrate'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:920:in `each'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:920:in `migrate'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:768:in `up'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:746:in `migrate'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/railties/databases.rake:42:in `block (2 levels) in <top (required)>'
ActiveRecord::StatementInvalid: PG::DuplicateColumn: ERROR:  column "email" of relation "users" already exists
: ALTER TABLE "users" ADD COLUMN "email" character varying(255) DEFAULT '' NOT NULL
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/postgresql/database_statements.rb:128:in `async_exec'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/postgresql/database_statements.rb:128:in `block in execute'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/abstract_adapter.rb:442:in `block in log'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activesupport-4.0.4/lib/active_support/notifications/instrumenter.rb:20:in `instrument'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/abstract_adapter.rb:437:in `log'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/postgresql/database_statements.rb:127:in `execute'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/abstract/schema_statements.rb:360:in `add_column'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/postgresql/schema_statements.rb:393:in `add_column'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/abstract/schema_definitions.rb:489:in `block (3 levels) in <class:Table>'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/abstract/schema_definitions.rb:488:in `each'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/abstract/schema_definitions.rb:488:in `block (2 levels) in <class:Table>'
/Users/AaronWilliamson/Ripelist-Classifieds/db/migrate/20140424074405_add_devise_to_users.rb:5:in `block in up'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/abstract/schema_statements.rb:334:in `change_table'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:629:in `block in method_missing'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:601:in `block in say_with_time'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:601:in `say_with_time'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:621:in `method_missing'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:387:in `method_missing'
/Users/AaronWilliamson/Ripelist-Classifieds/db/migrate/20140424074405_add_devise_to_users.rb:3:in `up'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:538:in `up'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:578:in `exec_migration'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:559:in `block (2 levels) in migrate'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:558:in `block in migrate'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:294:in `with_connection'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:557:in `migrate'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:713:in `migrate'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:963:in `block in execute_migration_in_transaction'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:1009:in `block in ddl_transaction'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/abstract/database_statements.rb:213:in `block in transaction'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/abstract/database_statements.rb:221:in `within_new_transaction'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/abstract/database_statements.rb:213:in `transaction'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/transactions.rb:209:in `transaction'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:1009:in `ddl_transaction'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:962:in `execute_migration_in_transaction'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:924:in `block in migrate'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:920:in `each'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:920:in `migrate'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:768:in `up'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:746:in `migrate'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/railties/databases.rake:42:in `block (2 levels) in <top (required)>'
PG::DuplicateColumn: ERROR:  column "email" of relation "users" already exists
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/postgresql/database_statements.rb:128:in `async_exec'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/postgresql/database_statements.rb:128:in `block in execute'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/abstract_adapter.rb:442:in `block in log'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activesupport-4.0.4/lib/active_support/notifications/instrumenter.rb:20:in `instrument'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/abstract_adapter.rb:437:in `log'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/postgresql/database_statements.rb:127:in `execute'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/abstract/schema_statements.rb:360:in `add_column'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/postgresql/schema_statements.rb:393:in `add_column'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/abstract/schema_definitions.rb:489:in `block (3 levels) in <class:Table>'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/abstract/schema_definitions.rb:488:in `each'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/abstract/schema_definitions.rb:488:in `block (2 levels) in <class:Table>'
/Users/AaronWilliamson/Ripelist-Classifieds/db/migrate/20140424074405_add_devise_to_users.rb:5:in `block in up'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/abstract/schema_statements.rb:334:in `change_table'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:629:in `block in method_missing'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:601:in `block in say_with_time'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:601:in `say_with_time'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:621:in `method_missing'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:387:in `method_missing'
/Users/AaronWilliamson/Ripelist-Classifieds/db/migrate/20140424074405_add_devise_to_users.rb:3:in `up'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:538:in `up'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:578:in `exec_migration'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:559:in `block (2 levels) in migrate'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:558:in `block in migrate'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:294:in `with_connection'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:557:in `migrate'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:713:in `migrate'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:963:in `block in execute_migration_in_transaction'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:1009:in `block in ddl_transaction'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/abstract/database_statements.rb:213:in `block in transaction'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/abstract/database_statements.rb:221:in `within_new_transaction'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/connection_adapters/abstract/database_statements.rb:213:in `transaction'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/transactions.rb:209:in `transaction'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:1009:in `ddl_transaction'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:962:in `execute_migration_in_transaction'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:924:in `block in migrate'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:920:in `each'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:920:in `migrate'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:768:in `up'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/migration.rb:746:in `migrate'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/activerecord-4.0.4/lib/active_record/railties/databases.rake:42:in `block (2 levels) in <top (required)>'
Tasks: TOP => db:migrate
(See full trace by running task with --trace)

另外，当我尝试运行像rake routes 这样的简单命令时，我得到了这个错误：

Aarons-iMac:ripelist-classifieds AaronWilliamson$ rake routes
rake aborted!
Gem::LoadError: You have already activated rake 10.3.1, but your Gemfile requires rake 10.2.2. Prepending `bundle exec` to your command may solve this.
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/bundler-1.5.3/lib/bundler/runtime.rb:34:in `block in setup'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/bundler-1.5.3/lib/bundler/runtime.rb:19:in `setup'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/bundler-1.5.3/lib/bundler.rb:119:in `setup'
/Users/AaronWilliamson/.gem/ruby/2.1.0/gems/bundler-1.5.3/lib/bundler/setup.rb:7:in `<top (required)>'
/Users/AaronWilliamson/Ripelist-Classifieds/config/boot.rb:4:in `<top (required)>'
/Users/AaronWilliamson/Ripelist-Classifieds/config/application.rb:1:in `<top (required)>'
/Users/AaronWilliamson/Ripelist-Classifieds/Rakefile:4:in `<top (required)>'
LoadError: cannot load such file -- bundler/setup
/Users/AaronWilliamson/Ripelist-Classifieds/config/boot.rb:4:in `<top (required)>'
/Users/AaronWilliamson/Ripelist-Classifieds/config/application.rb:1:in `<top (required)>'
/Users/AaronWilliamson/Ripelist-Classifieds/Rakefile:4:in `<top (required)>'
(See full trace by running task with --trace)

我的 Gemfile 如下所示：

source 'https://rubygems.org'

gem 'rails'
gem 'pg'
gem 'sass-rails'
gem 'uglifier'
gem 'coffee-rails'
gem 'jquery-rails'
gem 'turbolinks'
gem 'bcrypt'
gem "paperclip", :git => "git://github.com/thoughtbot/paperclip.git"
gem 'bootstrap-sass'
gem 'bootstrap-sass-extras'
gem 'email_validator'
gem 'devise'
gem 'dimensions-rails'
gem 'unicorn'

group :development do
  gem 'better_errors'
  gem 'binding_of_caller'
  gem 'quiet_assets'
  gem 'letter_opener'
end

group :test, :development do
  gem 'rspec-rails'
  gem 'factory_girl_rails'
  gem 'launchy'
  gem 'capybara'
  gem 'faker'
end

group :test do
  gem 'shoulda-matchers'
end

我使用的是 Rails 版本 4.0.4

我正在使用 ruby 版本 2.1.0p0（2013-12-25 修订版 44422）[x86_64-darwin13.0]

我对 Rails 相当陌生，因此非常感谢外行的术语来帮助我理解问题。我只想让我的应用程序运行，并使我的 rake 配置回到正轨。

【问题讨论】：

运行bundle install 时会发生什么？这能解决您的rake routes 问题吗？我认为您在这里有两个不同的问题...您的路线不依赖于数据库的当前状态。
bundle exec rake routes 将起作用。当您进行迁移时，用户表中的电子邮件列已经存在并且通过您的迁移，您正在尝试向用户添加另一个电子邮件列。这就是您收到错误的原因
我跑了 bundle 和 bundle install 但这并没有解决任何问题。 'bundle exec rake routes' 似乎给了我路线，但它没有做任何其他事情。我需要帮助的主要错误是：Aarons-iMac:ripelist-classifieds AaronWilliamson$ rake db:create rake aborted！ Gem::LoadError: 你已经激活了 rake 10.3.1，但是你的 Gemfile 需要 rake 10.2.2。将bundle exec 添加到您的命令可能会解决此问题。我不明白这个错误，我想把它放在不需要运行bundle exec的地方。

标签： ruby-on-rails ruby gem rake

【解决方案1】：

问题在于 gem rake，只需使用命令 bundle update rake 更新此 Gem，它会在运行 Migration 时解决问题。

【讨论】：

【解决方案2】：

来自您的日志：

PG::DuplicateColumn: 错误：关系“用户”的“电子邮件”列已经存在

这意味着在上次迁移20140424074405 AddDeviseToUsers 中，您尝试创建已存在的列。

尝试删除此迁移。关于 rake 也来自日志：

您已经激活了 rake 10.3.1，但是您的 Gemfile 需要 rake 10.2.2.在您的命令前添加 bundle exec 可以解决此问题。

这意味着然后你运行rake routes它是执行安装在系统上的rake，而不是在项目中运行在项目内部使用bundle exec rake routes

【讨论】：

我以前从未使用过bundle exec，你知道我怎样才能重新使用rake routes 甚至rake db:create，因为那根本不起作用？