diff --git a/apps/document_comments/__init__.py b/apps/document_comments/__init__.py
index 01619af003..7bc049db4d 100644
--- a/apps/document_comments/__init__.py
+++ b/apps/document_comments/__init__.py
@@ -1,6 +1,7 @@
 from django.utils.translation import ugettext_lazy as _
 from django.conf import settings
 from django.contrib.comments.models import Comment
+from django.contrib.contenttypes import generic
 
 from navigation.api import register_links, \
     register_model_list_columns
@@ -47,3 +48,12 @@ register_links(['comments_for_object', 'comment_add', 'comment_delete', 'comment
 register_links(Comment, [comment_delete])
 
 register_links(Document, [comments_for_object], menu_name='form_header')
+
+Document.add_to_class(
+    'comments',
+    generic.GenericRelation(
+        Comment,
+        content_type_field='content_type',
+        object_id_field='object_pk'
+    )
+)
diff --git a/apps/documents/models.py b/apps/documents/models.py
index b5366934e2..d2edaf0e91 100644
--- a/apps/documents/models.py
+++ b/apps/documents/models.py
@@ -15,11 +15,8 @@ from django.db import models
 from django.utils.translation import ugettext_lazy as _
 from django.utils.translation import ugettext
 from django.contrib.auth.models import User
-from django.contrib.contenttypes import generic
-from django.contrib.comments.models import Comment
 from django.core.exceptions import ValidationError
 
-from taggit.managers import TaggableManager
 from dynamic_search.api import register
 from converter.api import get_page_count
 from converter.api import get_available_transformations_choices
@@ -86,14 +83,6 @@ class Document(models.Model):
     description = models.TextField(blank=True, null=True, verbose_name=_(u'description'))
     date_added = models.DateTimeField(verbose_name=_(u'added'), db_index=True, editable=False)
 
-    tags = TaggableManager()
-
-    comments = generic.GenericRelation(
-        Comment,
-        content_type_field='content_type',
-        object_id_field='object_pk'
-    )
-
     @staticmethod
     def clear_image_cache():
         for the_file in os.listdir(CACHE_PATH):
diff --git a/apps/tags/__init__.py b/apps/tags/__init__.py
index 4b349e012e..c6170e4e28 100644
--- a/apps/tags/__init__.py
+++ b/apps/tags/__init__.py
@@ -7,6 +7,7 @@ from common.utils import encapsulate
 from documents.models import Document
 
 from taggit.models import Tag
+from taggit.managers import TaggableManager
 
 from tags.widgets import tag_color_block
 
@@ -61,3 +62,5 @@ register_links(Document, [tag_document_list], menu_name='form_header')
 register_links(['document_tags', 'tag_add_attach', 'tag_remove', 'tag_multiple_remove'], [tag_add_attach], menu_name='sidebar')
 
 register_multi_item_links(['document_tags'], [tag_document_remove_multiple])
+
+Document.add_to_class('tags', TaggableManager())