TYPE_ACTIVITY_ASK_TO_JOIN_GROUP is an Activity.activity_type that's
being used to create Activity objects but it's not been included in that
field's choices tuple! It is now. This means that in the admin list view
of Activity model we can now filter by this activity type.
Merge remote-tracking branch 'upstream/modal' into modal
Merge remote-tracking branch 'upstream/modal' into modal
Merge pull request #270 from knowledgepoint-devs/modal

TYPE_ACTIVITY_ASK_TO_JOIN_GROUP is an Activity.activity_type that's being used to create Activity objects but it's not been included in that field's choices tuple! It is now. This means that in the admin list view of Activity model we can now filter by this activity type.