public RoomController(IRoomViewModelReader reader, IRoomViewModelWriter writer)
        {
            Contract.Requires<ArgumentNullException>(reader != null); // Preconditions
            Contract.Requires<ArgumentNullException>(writer != null);

            this.reader = reader;
            this.writer = writer;
        }
        public RoomController(IRoomViewModelReader reader, IRoomViewModelWriter writer)
        {
            Contract.Requires <ArgumentNullException>(reader != null);
            Contract.Requires <ArgumentNullException>(writer != null);

            this.reader = reader;
            this.writer = writer;
        }