错误：耙子中止。未初始化的常量设置

Question

这里的新手试图为一个项目创建一个开发环境。我已经在我的设备上安装了 MySQL 和 Ruby on Rails。但是，在“捆绑安装”成功运行后尝试运行以下 3 个命令时，我遇到了以下错误消息。有什么想法吗？

1. bundle exec rake db:setup RAILS_ENV="development"
2. bundle exec rake db:migrate RAILS_ENV="development"
3. bundle exec rake db:seed RAILS_ENV=“development"

错误信息如下：

wcai-projects already exists
rake aborted!
uninitialized constant Settings

编辑-这是控制台日志：

$ bundle exec rake db:setup RAILS_ENV=development
/.rbenv/versions/2.2.3/lib/ruby/gems/2.2.0/gems/activesupport-3.2.12/lib/active_support/values/time_zone.rb:270: warning: circular argument reference - now
wcai-projects already exists
rake aborted!
uninitialized constant Settings
/wcai-web/config/initializers/carrier_wave.rb:4:in `block in <top (required)>'
/wcai-web/config/initializers/carrier_wave.rb:1:in `<top (required)>'
/wcai-web/config/environment.rb:5:in `<top (required)>'
Tasks: TOP => db:setup => db:schema:load_if_ruby => environment
(See full trace by running task with --trace)

编辑-config/initializers/carrier_wave.rb 的内容：

CarrierWave.configure do |config|
  config.fog_credentials = {
    :provider               => 'AWS',       # required
    :aws_access_key_id      => Settings.aws_access_key,      # required
    :aws_secret_access_key  => Settings.aws_secret_key       # required
#    :region                 => 'eu-west-1'  # optional, defaults to 'us-east-1'
  }
  config.fog_directory  = Settings.aws_bucket                    # required
  config.fog_public     = false     
  config.fog_authenticated_url_expiration = 120
  config.fog_attributes = {'Cache-Control'=>'max-age=315576000'}  # optional, defaults to {}
  #config.asset_host     = 'https://assets.example.com'            # optional, defaults to nil

end

Answer 1

将Gemfile 中的 Rails 版本更新到 4.2.4。然后输入bundle update rails 再试一次。