Mention and notify users when creating a status

bookwyrm/models/status.py

@@ -59,6 +59,7 @@ class Status(OrderedCollectionPageMixin, BookWyrmModel):
 
     @property
     def ap_tag(self):
+        ''' references to books and/or users '''
         tags = []
         for book in self.mention_books.all():
             tags.append(activitypub.Link(
@@ -66,6 +67,11 @@ class Status(OrderedCollectionPageMixin, BookWyrmModel):
                 name=book.title,
                 type='Book'
             ))
+        for user in self.mention_users.all():
+            tags.append(activitypub.Mention(
+                href=user.remote_id,
+                name=user.username,
+            ))
         return tags
 
     shared_mappings = [
@@ -270,7 +276,7 @@ class ReadThrough(BookWyrmModel):
 
 NotificationType = models.TextChoices(
     'NotificationType',
-    'FAVORITE REPLY TAG FOLLOW FOLLOW_REQUEST BOOST IMPORT')
+    'FAVORITE REPLY MENTION TAG FOLLOW FOLLOW_REQUEST BOOST IMPORT')
 
 class Notification(BookWyrmModel):
     ''' you've been tagged, liked, followed, etc '''