old_contents: from django.contrib.auth.models import User
  from django.contrib.contenttypes import generic
  from django.contrib.contenttypes.models import ContentType
  from django.db import models
  from django.utils.text import Truncator
  from django.utils.translation import ugettext_lazy as _
  from django.conf import settings
  from django_extensions.db.fields import ModificationDateTimeField, CreationDateTimeField
  from .managers import ReactionManager
  
  
  REACTION_MAX_LENGTH = getattr(settings, 'REACTION_MAX_LENGTH', 500)
  
  
  class Reaction(models.Model):
      """
      A user reaction about some object. This model is based on the Comments model
      from django.contrib.comments.
      """
  
      # Content-object field.
      content_type = models.ForeignKey(ContentType, verbose_name=_('content type'), related_name="content_type_set_for_%(class)s")
      object_pk = models.IntegerField(_('object ID'))
      content_object = generic.GenericForeignKey(ct_field="content_type", fk_field="object_pk")
  
      # Who posted this reaction. User will need to be logged in to make a reaction.
      author = models.ForeignKey(User, verbose_name=_('author'), related_name="%(class)s_reactions")
      editor = models.ForeignKey(User, verbose_name=_('editor'), blank=True, null=True, help_text=_("The last user to edit this reaction."))
  
      # The reaction text.
      reaction = models.TextField(_('reaction'), max_length=REACTION_MAX_LENGTH)
  
      # Metadata about the reaction.
      created = CreationDateTimeField(_('created'))
      updated = ModificationDateTimeField(_('updated'))
      ip_address = models.IPAddressField(_('IP address'))
  
      # Manager
      objects = ReactionManager()
  
      class Meta:
          ordering = ('created',)
          verbose_name = _('reaction')
          verbose_name_plural = _('reactions')
  
      def __unicode__(self):
          s = "{0}: {1}".format(self.author.get_full_name(), self.reaction)
          return Truncator(s).words(10)
  
      def save(self, *args, **kwargs):
          if self.editor is None:
              self.editor = self.author
          super(Reaction, self).save(*args, **kwargs)
  
new_contents: from django.contrib.auth.models import User
  from django.contrib.contenttypes import generic
  from django.contrib.contenttypes.models import ContentType
  from django.db import models
  from django.utils.text import Truncator
  from django.utils.translation import ugettext_lazy as _
  from django.conf import settings
  from django_extensions.db.fields import ModificationDateTimeField, CreationDateTimeField
  from .managers import ReactionManager
  
  
  REACTION_MAX_LENGTH = getattr(settings, 'REACTION_MAX_LENGTH', 500)
  
  
  class Reaction(models.Model):
      """
      A user reaction about some object. This model is based on the Comments model
      from django.contrib.comments.
      """
  
      # Content-object field.
      content_type = models.ForeignKey(ContentType, verbose_name=_('content type'), related_name="content_type_set_for_%(class)s")
      object_pk = models.PositiveIntegerField(_('object ID'))
      content_object = generic.GenericForeignKey(ct_field="content_type", fk_field="object_pk")
  
      # Who posted this reaction. User will need to be logged in to make a reaction.
      author = models.ForeignKey(User, verbose_name=_('author'), related_name="%(class)s_reactions")
      editor = models.ForeignKey(User, verbose_name=_('editor'), blank=True, null=True, help_text=_("The last user to edit this reaction."))
  
      # The reaction text.
      reaction = models.TextField(_('reaction'), max_length=REACTION_MAX_LENGTH)
  
      # Metadata about the reaction.
      created = CreationDateTimeField(_('created'))
      updated = ModificationDateTimeField(_('updated'))
      ip_address = models.IPAddressField(_('IP address'))
  
      # Manager
      objects = ReactionManager()
  
      class Meta:
          ordering = ('created',)
          verbose_name = _('reaction')
          verbose_name_plural = _('reactions')
  
      def __unicode__(self):
          s = "{0}: {1}".format(self.author.get_full_name(), self.reaction)
          return Truncator(s).words(10)
  
      def save(self, *args, **kwargs):
          if self.editor is None:
              self.editor = self.author
          super(Reaction, self).save(*args, **kwargs)
  
subject: Change Integer to PostiveInteger in Reaction model.