We can do this in html file (after this we should include our script):

<vue-app>[[ message ]]</vue-app>

new Vue({
  el: 'vue-app',
  delimiters: ['[[', ']]'],
  data: {
    message: "Hello Vue! caca de la vaca!"
  }
});

O con una inline template:

new Vue({
  el: 'vue-app',
  data: {
    message: "Hello Vue! caca de la vaca!"
  },
  template: `<div>{{ message }}</div>`
});

"use strict";

require(
  ['../static/js/test.js'], 
  function() {
    new Vue({
      el: 'user-app',
      template: `
    <div>
      {{ message }} <button-counter></button-counter>
    </div>`,
      data: {
        message: "Hello Vue! caca de la vaca!"
      }
    });
});

test.js:

"use strict";

Vue.component('button-counter', {
    data: function () {
        return {
            count: 0
        }
    },
    template: '<button v-on:click="count++">You clicked me {{ count }} times.</button>'
})