我有一些模型，包括自定义用户喜欢：

class User(AbstractUser):

    image = models.ImageField(upload_to=get_image_path, blank=True, null=True)
    objects = NewUserManager()

    USERNAME_FIELD = 'username'
    REQUIRED_FIELDS = ['email']

    def __str__(self):
        return self.email

    class Meta(AbstractUser.Meta):
        swappable = 'stack.User'

这与我已经拥有的其他模型配合得很好，直到我试图再添加一个类：

class Vote(models.Model):

    rate_type = models.BooleanField()
    question = models.ForeignKey("Question", related_name='question_rate', on_delete=models.PROTECT)
    answer = models.ForeignKey("Answer", related_name='answer_rate', on_delete=models.PROTECT)
    user = models.ForeignKey(get_user_model(), on_delete=models.PROTECT)

    class Meta:
        unique_together = [('question', 'user'), ('answer', 'user'), ]

很遗憾，尝试迁移时出现错误：

Traceback (most recent call last):
      File "manage.py", line 15, in <module>
        execute_from_command_line(sys.argv)
      File "/home/artem/.local/lib/python3.5/site-packages/django/core/management/__init__.py", line 371, in execute_from_command_line
        utility.execute()
      File "/home/artem/.local/lib/python3.5/site-packages/django/core/management/__init__.py", line 365, in execute
        self.fetch_command(subcommand).run_from_argv(self.argv)
      File "/home/artem/.local/lib/python3.5/site-packages/django/core/management/base.py", line 288, in run_from_argv
        self.execute(*args, **cmd_options)
      File "/home/artem/.local/lib/python3.5/site-packages/django/core/management/base.py", line 335, in execute
        output = self.handle(*args, **options)
      File "/home/artem/.local/lib/python3.5/site-packages/django/core/management/commands/makemigrations.py", line 159, in handle
        migration_name=self.migration_name,
      File "/home/artem/.local/lib/python3.5/site-packages/django/db/migrations/autodetector.py", line 44, in changes
        changes = self._detect_changes(convert_apps, graph)
      File "/home/artem/.local/lib/python3.5/site-packages/django/db/migrations/autodetector.py", line 192, in _detect_changes
        self._build_migration_list(graph)
      File "/home/artem/.local/lib/python3.5/site-packages/django/db/migrations/autodetector.py", line 270, in _build_migration_list
        resolved_app_label, resolved_object_name = getattr(settings, dep[1]).split('.')
      File "/home/artem/.local/lib/python3.5/site-packages/django/conf/__init__.py", line 57, in __getattr__
        val = getattr(self._wrapped, name)
    AttributeError: 'Settings' object has no attribute 'stack.User'

我对此感到困惑，因为我既没有更改settings.py，也没有更改其他任何内容。我可以删除“Vote”类中对用户的引用，然后它再次恢复正常，但不幸的是，我需要将其保留在这里。同一文件中的大多数其他模型确实通过ForeignKey和“get_user_model”对用户类有相同的引用（）”函数（也许我试着用用户类本身切换它-相同的结果）-它的工作原理只有不同，我在几次迁移前添加了它们。
django版本2.0.2来自settings.py:

# Application definition

INSTALLED_APPS = [
    'stack.apps.StackConfig',
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
]

AUTH_USER_MODEL = 'stack.User'

wsgi.py:

import os

from django.core.wsgi import get_wsgi_application

os.environ.setdefault("DJANGO_SETTINGS_MODULE", "StackOverflow.settings")

application = get_wsgi_application()

apps.py:

class StackConfig(AppConfig):
name = 'stack'

也许有人曾经面对过它，或者只是知道如何摆脱这个错误的解决方案？