Django связка Users и своим profile

Прошу помочь, как мне добиться при создании users что бы он автоматом добавил пользователя в моделе Student, вот код он у меня выводит ошибку

IntegrityError at /admin/auth/user/add/ FOREIGN KEY constraint failed

models.py

from django.db import models
from django.conf import settings
from django.contrib.auth.models import User
from django.db.models.signals import post_save
from django.dispatch import receiver

class Student(models.Model):
    user = models.OneToOneField(User,
        on_delete=models.CASCADE)
    group = models.ForeignKey(Group,on_delete=models.CASCADE,default=0)
    date_pub = models.DateTimeField(auto_now_add=True)
    completed = models.BooleanField(default=False)

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

    class Meta:
        verbose_name = 'Студент'
        verbose_name_plural = 'Студенты'
        ordering = ('-date_pub',)

@receiver(post_save, sender=User)
def create_user_profile(sender, instance, created, **kwargs):
    if created:
        Student.objects.create(user=instance)

@receiver(post_save, sender=User)
def save_user_profile(sender, instance, **kwargs):
    instance.student.save()