解决更改AUTH_USER_MODEL后出现的问题

from django.db import models
from django.contrib.auth.models import AbstractUser

class UserProfile(AbstractUser):
 nick_name = models.CharField(max_length=50,verbose_name=u"昵称", default="")
 birday = models.DateField(verbose_name=u"生日", null=True, blank=True)
 gender = models.CharField(max_length=5, choices=(("male",u"男"),("female",u"女")), default="female")
 address = models.CharField(max_length=100, default=u"")
 mobile = models.CharField(max_length=11, null=True, blank=True)
 image = models.ImageField(upload_to="image/%Y/%m", default=u"image/default.png", max_length=100)

 class Meta:
  verbose_name = "用户信息"
  verbose_name_plural = verbose_name

 def __str__(self):
  return self.username