old_contents: import uuid
  
  from django.contrib.auth.models import User
  from django.db import models
  from django.dispatch import receiver
  
  from comics.core.models import Comic
  
  
  @receiver(models.signals.post_save, sender=User)
  def create_user_profile(sender, instance, created, **kwargs):
      if created:
          UserProfile.objects.create(user=instance)
  
  
  def make_secret_key():
      return uuid.uuid4().hex
  
  
  class UserProfile(models.Model):
      user = models.OneToOneField(User, related_name='comics_profile')
      secret_key = models.CharField(max_length=32, blank=False,
          default=make_secret_key,
          help_text='Secret key for feed and API access')
      comics = models.ManyToManyField(Comic)
  
      class Meta:
          db_table = 'comics_user_profile'
  
      def __unicode__(self):
          return u'User profile for %s' % self.user
  
      def generate_new_secret_key(self):
          self.secret_key = make_secret_key()
  
new_contents: import uuid
  
  from django.contrib.auth.models import User
  from django.db import models
  from django.dispatch import receiver
  
  from comics.core.models import Comic
  
  
  @receiver(models.signals.post_save, sender=User)
  def create_user_profile(sender, instance, created, **kwargs):
      if created:
          UserProfile.objects.create(user=instance)
  
  
  def make_secret_key():
      return uuid.uuid4().hex
  
  
  class UserProfile(models.Model):
      user = models.OneToOneField(User, related_name='comics_profile')
      secret_key = models.CharField(max_length=32, blank=False,
          default=make_secret_key,
          help_text='Secret key for feed and API access')
      comics = models.ManyToManyField(Comic, through='Subscription')
  
      class Meta:
          db_table = 'comics_user_profile'
  
      def __unicode__(self):
          return u'User profile for %s' % self.user
  
      def generate_new_secret_key(self):
          self.secret_key = make_secret_key()
  
  
  class Subscription(models.Model):
      userprofile = models.ForeignKey(UserProfile)
      comic = models.ForeignKey(Comic)
  
      class Meta:
          db_table = 'comics_user_profile_comics'
  
subject: Add a M2M table for the subscription relation between users and comics