Timeline manager (#40)

* start messing about with timeline manager

* i have no idea what i'm doing

* i continue to not know what i'm doing

* it's coming along

* bit more progress

* update timeline with new posts as they come in

* lint and fmt

* Select accounts where empty string

* restructure a bunch, get unfaves working

* moving stuff around

* federate status deletes properly

* mention regex better but not 100% there

* fix regex

* some more hacking away at the timeline code phew

* fix up some little things

* i can't even

* more timeline stuff

* move to ulid

* fiddley

* some lil fixes for kibou compatibility

* timelines working pretty alright!

* tidy + lint

internal/federation/federatingdb/undo.go

@@ -48,6 +48,9 @@ func (f *federatingDB) Undo(ctx context.Context, undo vocab.ActivityStreamsUndo)
 	}
 
 	for iter := undoObject.Begin(); iter != undoObject.End(); iter = iter.Next() {
+		if iter.GetType() == nil {
+			continue
+		}
 		switch iter.GetType().GetTypeName() {
 		case string(gtsmodel.ActivityStreamsFollow):
 			// UNDO FOLLOW