On user making, check if we have a user with that uri.

lib/pleroma/web/ostatus/ostatus.ex

@@ -235,10 +235,14 @@ def make_user(uri) do
         info: info,
         avatar: info["avatar"]
       }
+      with %User{} = user <- User.get_by_ap_id(data.ap_id) do
+        {:ok, user}
+      else _e ->
         cs = User.remote_user_creation(data)
         Repo.insert(cs)
       end
     end
+  end
 
   # TODO: Just takes the first one for now.
   def make_avatar_object(author_doc) do