class FreelanceSite(models.Model):
    name = models.CharField(max_length=50)
    url = models.URLField(unique=True)
    description = models.TextField()
    rss_feed = models.URLField(unique=True)
    favicon = models.ImageField(upload_to='favicons/')
    
    def __unicode__(self):
        return self.name

class SiteCategory(models.Model):
    freelance_site = models.ForeignKey(FreelanceSite)
    site_category = models.CharField(max_length=70)
    
    def __unicode__(self):
        return self.site_category

#пример модели
class UsersCategory(models.Model):
    user = models.ForeignKey(User)
    categories = models.ManyToManyField(SiteCategory)
    
    def get_absolute_url(self):
        return "/users_category/%i/" % self.id
    
    def __unicode__(self):
        return self.user.username