anchor.diff:  
   from_map(server, Map) ->
       #server{
  -       id = maps:get(<<"id">>, Map, 0),
  +       id = objectid_to_id(maps:get(<<"_id">>, Map, 0)),
          registration = maps:get(<<"registration">>, Map, true),
          readonly = maps:get(<<"readonly">>, Map, false),
          map = maps:get(<<"map">>, Map, <<"">>),
  
positive.code:     do_create_indexses(State),
      case do_get_server(State) of
          {error, _Reason} ->
              do_create_server(State, #server{id = gen_uid()});
          {ok, _Server} -> void
      end,
      case do_count_users(State) of
  
negative.code:     mongoc:transaction(Topology, fun(Worker) -> mc_worker_api:count(Worker, ?COLLECTION_USERS, #{}) end).
  
  do_create_user(#state{topology = Topology}, Rec) ->
      Map = to_map(user, Rec#user{id = gen_id(), hashPassword = hash(Rec#user.password)}),
      Callback = fun(Worker) ->
                         mc_worker_api:insert(Worker, ?COLLECTION_USERS, Map)
                 end,
  