text: from django.db import models
  from django.utils import timezone
  
  
  class Article(models.Model):
      title = models.CharField(max_length=100)
      pub_date = models.DateField()
      pub_datetime = models.DateTimeField(default=timezone.now)
  
      categories = models.ManyToManyField("Category", related_name="articles")
  
  
  class Comment(models.Model):
      article = models.ForeignKey(Article, models.CASCADE, related_name="comments")
      text = models.TextField()
      pub_date = models.DateField()
      approval_date = models.DateField(null=True)
  
  
  class Category(models.Model):
      name = models.CharField(max_length=255)
  