Use one-to-one relationships in Django2.0 models

 File "/Users/topaz/Desktop/Project/PWO/models.py", line 110, in UserProfile
 user = models.OneToOneField(User)
 TypeError: __init__() missing 1 required positional argument: 'on_delete'

 1.找到报错行
 user = models.OneToOneField(User)

 2.添加 models.CASCADE
 user = models.OneToOneField(User,models.CASCADE)

 之前用的 django1.8 版本，升级后的2.0版本发生变化，需要设置 'on_delete'= models.CASCADE 才能正常使用。