Use model polymorphism

note_kfet/settings.py

@@ -32,6 +32,11 @@ INSTALLED_APPS = [
     # Theme overrides Django Admin templates
     'theme',
 
+    # External apps
+    'polymorphic',
+    'guardian',
+    'reversion',
+
     # Django contrib
     'django.contrib.admin',
     'django.contrib.admindocs',
@@ -42,10 +47,6 @@ INSTALLED_APPS = [
     'django.contrib.messages',
     'django.contrib.staticfiles',
 
-    # External apps
-    'guardian',
-    'reversion',
-
     # Note apps
     'activity',
     'member',
@@ -120,6 +121,8 @@ AUTHENTICATION_BACKENDS = (
     'guardian.backends.ObjectPermissionBackend',
 )
 
+GUARDIAN_GET_CONTENT_TYPE = 'polymorphic.contrib.guardian.get_polymorphic_base_content_type'
+
 # Internationalization
 # https://docs.djangoproject.com/en/2.2/topics/i18n/