docs: function( userId, id ) {
  
  		return this.memory.leaveRoom( userId, id )
  		.then( function( numUsers ) {
  
  			if( numUsers == 0 ) {
  
  				// remove all listeners from room since there should be one
  				rooms[ id ].removeAllListeners();
  				rooms[ id ].setPrivate();
  				delete rooms[ id ];
  				
  				return promise.resolve( null );
  			} else {
  
  				return promise.resolve( rooms[ id ] );
  			}
  		});
  	}