Add tag attach and tag remove events.

Signed-off-by: Roberto Rosario <roberto.rosario.gonzalez@gmail.com>

HISTORY.rst

@@ -34,6 +34,7 @@
 - Remove the view to submit all document for OCR.
 - When changing document types, don't delete the old metadata that is
   also found in the new document type. GitLab issue #421.
+- Add tag attach and tag remove events.
 
 2.6.4 (2017-07-26)
 ==================

mayan/apps/tags/apps.py

@@ -36,6 +36,7 @@ class TagsApp(MayanAppConfig):
 
     def ready(self):
         super(TagsApp, self).ready()
+        from actstream import registry
 
         Document = apps.get_model(
             app_label='documents', model_name='Document'
@@ -143,3 +144,4 @@ class TagsApp(MayanAppConfig):
                 'tags:single_document_multiple_tag_remove'
             )
         )
+        registry.register(Tag)

mayan/apps/tags/events.py

@@ -0,0 +1,14 @@
+from __future__ import absolute_import, unicode_literals
+
+from django.utils.translation import ugettext_lazy as _
+
+from events.classes import Event
+
+event_tag_attach = Event(
+    name='tag_attach',
+    label=_('Tag attached to document')
+)
+event_tag_remove = Event(
+    name='tag_remove',
+    label=_('Tag removed from document')
+)

mayan/apps/tags/models.py

@@ -11,6 +11,8 @@ from acls.models import AccessControlList
 from documents.models import Document
 from documents.permissions import permission_document_view
 
+from .events import event_tag_attach, event_tag_remove
+
 
 @python_2_unicode_compatible
 class Tag(models.Model):
@@ -33,8 +35,11 @@ class Tag(models.Model):
         verbose_name = _('Tag')
         verbose_name_plural = _('Tags')
 
-    def attach_to(self, document):
+    def attach_to(self, document, user=None):
         self.documents.add(document)
+        event_tag_attach.commit(
+            action_object=self, actor=user, target=document
+        )
 
     def get_document_count(self, user):
         queryset = AccessControlList.objects.filter_by_access(
@@ -43,8 +48,11 @@ class Tag(models.Model):
 
         return queryset.count()
 
-    def remove_from(self, document):
+    def remove_from(self, document, user=None):
         self.documents.remove(document)
+        event_tag_remove.commit(
+            action_object=self, actor=user, target=document
+        )
 
 
 class DocumentTag(Tag):