code: function( roomID ) {
  
  		if( keys.length > 0 ) {
  
  			var randIdx = Math.round( Math.random() * ( keys.length - 1 ) ),
  				key = keys.splice( randIdx, 1 )[ 0 ];
  
  			keyToId[ key ] = roomID;
  			idToKey[ roomID ] = key;
  
  			return promise.resolve( key );
  		} else {
  
  			return promise.reject( 'Run out of keys' );
  		}
  	}
docs: get a key which can be used to enter a room vs entering room via
  roomID
  
  @param  {String} roomID id of the room you'd like a key for
  @return {Promise} A promise will be returned which will return a roomKey on success