code: function( key ) {
  
  		var savedRoomId = keyToId[ key ];
  
  		if( savedRoomId ) {
  
  			return promise.resolve( savedRoomId );
  		} else {
  
  			return promise.reject();
  		}
  	}
docs: return the room id for the given key
  
  @param  {String} key key used to enter the room
  @return {Promise} This promise will succeed with the room id and fail if no room id exists for key