sName:'rally'},
	{"content": "WSR", "id": "WSR", "value": 16, className:'openwheel'},
	{"content": "Roads", "id": "Roads", "value": 17, className:'motorcycle'},
	{"content": "WEC", "id": "WEC", "value": 18, className:'endurance'},
	{"content": "GP2", "id": "GP2", "value": 19, className:'openwheel'}
  ]);

  // function to make all groups visible again
  function showAllGroups(){
    groups.forEach(function(group){
      groups.update({id: group.id, visible: true});
    })
  };

  // create a dataset with it