from django.contrib.auth.models import AbstractUser, Group, Permission
from django.db import models

class User(AbstractUser):
    full_name = models.CharField(max_length=150, blank=True)
    bio = models.TextField(blank=True)
    avatar = models.ImageField(upload_to='avatars/', null=True, blank=True)

    # Переопределяем поля групп и разрешений, чтобы избежать конфликтов обратных связей
    groups = models.ManyToManyField(
        Group,
        related_name='custom_user_set',
        blank=True,
        help_text='The groups this user belongs to.',
        verbose_name='groups',
    )
    user_permissions = models.ManyToManyField(
        Permission,
        related_name='custom_user_set',
        blank=True,
        help_text='Specific permissions for this user.',
        verbose_name='user permissions',
    )

    def __str__(self):
        return self.username
```python
from django.contrib.auth.models import AbstractUser
from django.db import models

class User(AbstractUser):
    full_name = models.CharField(max_length=150, blank=True)
    bio = models.TextField(blank=True)
    avatar = models.ImageField(upload_to='avatars/', null=True, blank=True)

    def __str__(self):
        return self.username