persistentFooterButtons: <Widget>[
        RaisedButton(
          onPressed: () {},
          color: BLUE,
          child: Icon(
            Icons.add,
            color: Colors.white,
          ),
        ),
        RaisedButton(
          onPressed: () {
          },
          color: RED,
          child: Icon(
            Icons.clear,
            color: Colors.white,
          ),
        ),
      ],