old_contents: from django.db import models
  from django.utils.translation import ugettext_lazy as _
  
  from django.contrib.auth.models import User
  
  
  class Category(models.Model):
      name = models.CharField(_("Name"), max_length=255, unique=True)
  
  
  class Forum(models.Model):
      category = models.ForeignKey(Category, related_name='forums')
      name = models.CharField(_("Name"), max_length=255)
      description = models.TextField(_("Description"), blank=True)
  
new_contents: from django.db import models
  from django.utils.translation import ugettext_lazy as _
  
  from django.contrib.auth.models import User
  
  
  class Category(models.Model):
      name = models.CharField(_("Name"), max_length=255, unique=True)
  
  
  class Forum(models.Model):
      category = models.ForeignKey(Category, related_name='forums')
      name = models.CharField(_("Name"), max_length=255)
      description = models.TextField(_("Description"), blank=True)
  
  
  class Topic(models.Model):
      forum = models.ForeignKey(Forum, related_name='topics')
      name = models.CharField(_("Name"), max_length=255)
      last_post = models.ForeignKey('Post', verbose_name=_("Last post"), related_name='forum_last_post', blank=True, null=True)
  
  
  
  class Post(models.Model):
      topic = models.ForeignKey(Topic, related_name='posts')
      user = models.ForeignKey(User, related_name='forum_posts')
      created = models.DateTimeField(_("Created"), auto_now_add=True)
      updated = models.DateTimeField(_("Updated"),auto_now=True)
      body = models.TextField(_("Body"))
  
subject: add basic models for topics and posts