text: var checklist = new Vue({
    el: '#app',
    // data: {
    //   checked: true
    // }
    data: {
      itemSet1: [],
      itemSet2: []
    },
    computed: {
      totalItems: function() {
        var total = this.itemSet1.concat(this.itemSet2);
        return total.length;
      }
    }
  });
  
  