class Article(models.Model):
title = models.CharField(max_length=128, verbose_name='Заголовок статьи')
slug_a = models.SlugField(unique=True)
link = models.ForeignKey('Category', on_delete=models.PROTECT, blank=True)
class Category(models.Model):
theme = models.CharField(max_length=64, db_index=True, verbose_name='Категория')
slug_c = models.SlugField(blank=True)