Fixes bugs in how lists/shelves federate Adds

bookwyrm/activitypub/__init__.py

@@ -16,7 +16,7 @@ from .response import ActivitypubResponse
 from .book import Edition, Work, Author
 from .verbs import Create, Delete, Undo, Update
 from .verbs import Follow, Accept, Reject, Block
-from .verbs import Add, AddBook, Remove
+from .verbs import Add, AddBook, AddListItem, Remove
 
 # this creates a list of all the Activity types that we can serialize,
 # so when an Activity comes in from outside, we can check if it's known