使用“列用户名不是唯一错误”创建自定义配置文件

Question

我正在尝试扩展Django-allauth中的基本用户配置文件。注册表单正确加载，但在提交表单后，“列用户名不是唯一错误”。

项目文件如下：

models.py

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

# Create your models here.
class UserProfile(models.Model):

    user = models.OneToOneField(User, related_name='userprofile')

    # The additional attributes we wish to include.
    website = models.URLField(blank=True)
    picture = models.ImageField(upload_to='profile_images', blank=True)
    has_accepted_tos = models.BooleanField(default=False,
                                            verbose_name='I accept site rules')
    #REQUIRED_FIELDS = ['has_accepted_tos']

    def __unicode__(self):
        return self.user.username

    User.profile = property(lambda u:UserProfile.objects.get_or_create(user=u)[0])

forms.py

from django.contrib.auth import get_user_model
from .models import UserProfile
from django.forms import CharField, BooleanField, ModelForm
from django.utils.translation import ugettext as _
from allauth.account.adapter import get_adapter

# forms.py

    class SignupForm(ModelForm):

        has_accepted_tos = BooleanField(error_messages={'required': _('You must accept the terms and conditions')}, 
                                            label=_('I accept site terms and conditions'), 
                                            required=True)

        class Meta:
            #model = get_user_model
            model = UserProfile
            fields = ('website', 'picture', 'has_accepted_tos') 

        def signup(self, request, user):
            adapter = get_adapter()
            user = adapter.new_user(request)
            adapter.save_user(request, user, self)

我怀疑注册方法没有正确实现。有人可以建议吗？