model_example.py

# model.py in the Django app called users
from django.db import models
from django.contrib.auth.models import AbstractUser


# class to define choices
class Category(models.TextChoices):
    GUEST = 'G', 'Guest user'
    COMMON_USER = 'C', 'Common user'
    ADMIN = 'A', 'Admin user'


# user model that inherits from AbstractUser
# there is no need to define a username field
# because is defined in the parent class
class User(AbstractUser):
    phone_number = models.CharField(max_length=50, blank=True, null=True)
    category = models.CharField(
        max_length=1,
        choices=Category.choices,
        default='G',
    )