<filename>pizzashopapp/models.py
from django.db import models
from django.contrib.auth.models import User


# Create your models here.

class PizzaShop(models.Model):
    owner = models.OneToOneField(User, on_delete=models.CASCADE, related_name='pizzashop')
    name = models.CharField(max_length = 20)
    phone = models.CharField(max_length = 20)
    adress = models.CharField(max_length = 20)
    logo = models.ImageField(upload_to='pizzashop_logo/', blank=False)

    def __str__(self):
        return self.name


class Pizza(models.Model):
    pizzashop = models.ForeignKey(PizzaShop,on_delete=models.CASCADE,)
    name = models.CharField(max_length = 20)
    short_desc = models.CharField(max_length = 20)
    image = models.ImageField(upload_to='pizza_images/', blank=False)
    price = models.IntegerField(default=0)

    def __str__(self):
        return self.name


class Client(models.Model):
    user = models.OneToOneField(User, on_delete=models.CASCADE, related_name='client')
    avatar = models.CharField(max_length = 500)
    #blank = True не обязательно к заполнению
    phone = models.CharField(max_length = 20, blank=True)
    address = models.CharField(max_length = 30, blank=True)
    
    def __str__(self):
        return self.user.get_full_name

<filename>pizzashopapp/models.py
from django.db import models
from django.contrib.auth.models import User


# Create your models here.

class PizzaShop(models.Model):
    owner = models.OneToOneField(User, on_delete=models.CASCADE, related_name='pizzashop')
    name = models.CharField(max_length = 20)
    phone = models.CharField(max_length = 20)
    adress = models.CharField(max_length = 20)
    logo = models.ImageField(upload_to='pizzashop_logo/', blank=False)

    def __str__(self):
        return self.name


class Pizza(models.Model):
    pizzashop = models.ForeignKey(PizzaShop,on_delete=models.CASCADE,)
    name = models.CharField(max_length = 20)
    short_desc = models.CharField(max_length = 20)
    image = models.ImageField(upload_to='pizza_images/', blank=False)
    price = models.IntegerField(default=0)

    def __str__(self):
        return self.name


class Client(models.Model):
    user = models.OneToOneField(User, on_delete=models.CASCADE, related_name='client')
    avatar = models.CharField(max_length = 500)
    #blank = True не обязательно к заполнению
    phone = models.CharField(max_length = 20, blank=True)
    address = models.CharField(max_length = 30, blank=True)
    
    def __str__(self):
        return self.user.get_full_name

# Create your models here. #blank = True не обязательно к заполнению