新建 Django 项目的时候 后台运行会出现一些报错的一些英文句子，但不影响运行。
句子是：
You have 14 unapplied migration(s). Your project may not work properly until you apply the migrations for app(s): admin, auth, contenttypes, sessions.
Run 'python manage.py migrate' to apply them.
February 14, 2019 - 11:13:41
Django version 2.0.4, using settings 'kaoshi.settings'
Starting development server at http://127.0.0.1:8000/
Quit the server with CTRL-BREAK.
解决方法：执行一下这个：python manage.py migrate
它可以让我们在修改Model后可以在不影响现有数据的前提下重建表结构。