如何将以下常规JavaScript代码转换为VueJS？

// 常规JavaScript代码
var app = document.getElementById('app');
var count = 0;

function increment() {
  count++;
  app.innerHTML = 'Count: ' + count;
}

function decrement() {
  count--;
  app.innerHTML = 'Count: ' + count;
}

app.innerHTML = 'Count: ' + count;

<!-- HTML文件 -->
<div id="app">
  Count: {{ count }}
  <button v-on:click="increment">Increment</button>
  <button v-on:click="decrement">Decrement</button>
</div>

<!-- JavaScript文件 -->
<script src="https://cdn.jsdelivr.net/npm/vue"></script>
<script>
  var app = new Vue({
    el: '#app',
    data: {
      count: 0
    },
    methods: {
      increment: function() {
        this.count++;
      },
      decrement: function() {
        this.count--;
      }
    }
  });
</script>