raise FieldDoesNotExist('%s has no field named %r' % (self.object_name, field_name))
django.core.exceptions.FieldDoesNotExist: User has no field named 'auth.User'

 # ...ещё импорты...
from django.contrib.auth.models import User
#
class Post(models.Model):
    author = models.ForeignKey('auth.User')
    title = models.CharField("Наименование", max_length=200)
    category = models.CharField("Категория", max_length=50, default="Пицца")
    ingridients = models.TextField("Ингридиенты")
    description = models.TextField("Описание и история")
    price = models.DecimalField("Цена", default=0.0, max_digits=4, decimal_places=2)
    weight = models.CharField("Вес (мини,миди,макси)", validators=[v.validate_comma_separated_integer_list], max_length=20, blank=True, null=True)
    diameter = models.CharField("Диаметр (мини,миди,макси)", validators=[v.validate_comma_separated_integer_list], max_length=20, blank=True, null=True)
    image = models.ImageField("Изображение", upload_to='img/user_media/', blank=True, null=True)
    created_date = models.DateTimeField("Дата создания", default=timezone.now)
    published_date = models.DateTimeField("Дата публикации", blank=True, null=True)
#####
class Profile(models.Model):
    user = models.OneToOneField(User, settings.AUTH_USER_MODEL, primary_key=True)
    orders = models.CharField(default="Нет заказов", max_length=500)
    def __str__(self):
        return 'Профиль пользователя {}'.format(self.user.username)

 def user_profile(request):
    profile = Profile.objects.get(pk=request.user.id)
    return render(request, 'yummy_site/user_profile.html', {'profile': profile})

 author = models.ForeignKey(User)