<div id="root">
  <ul>
    <li v-for="(on, index) in list" v-bind:key="on.key">{{ on.title }}<button v-on:click="deleteList(index)">Delete</button></li>
  </ul>
  <input v-model="gulp">
  <br>
  <button v-on:click="addList">Add</button>
</div>

  const vm = new Vue({
    el: '#root',
    data: {
      list: [],
      keys: '',
      gulp: '',
    },
    methods: {
      addList: function() {
        this.list.push({ title: this.gulp, key: this.keys++ });
      },
      deleteList: function(num) {
        this.list.splice(num, 1);
      },
    },
  });