title: Issue using a Vue component (with video.js) in rails
body: <p>I got this vue component in rails.</p>
  
  <pre><code>&lt;template&gt;
   &lt;div class="hello"&gt;
     &lt;h1&gt;THIS IS VUE&lt;h1/&gt;
  
  &lt;video id="videok" class="video-js vjs-default-skin vjs-big-play-centered" 
   controls preload="auto" width="1500" height="700"
   poster="../../../assets/images/logo.png"
   data-setup='{"example_option":true}'&gt;
  &lt;source src="../../../assets/videos/vid.mp4" type="video/mp4" /&gt;
  
  &lt;/video&gt;
  
  &lt;/div&gt;
  
  &lt;/template&gt;
  
  &lt;script lang="ts"&gt;
  
  import { Component, Prop, Vue } from 'vue-property-decorator';
  import videojs from 'video.js';
  
  
  @Component
  export default class VideoVue extends Vue {
  
   protected player: any;
  
   mounted() {
  
     this.player = videojs("videok");
  
  }
  
  }
  
  &lt;/script&gt;
  
  &lt;style scoped lang="css"&gt;
  @import '../../src/video.js/dist/video-js.css';
  
  &lt;/style&gt;
  
  </code></pre>
  
  <p>I call this component as follows (from a <code>.html.erb</code> file)</p>
  
  <pre><code>&lt;%= javascript_pack_tag 'hello_vue' %&gt;
  &lt;%= stylesheet_pack_tag 'hello_vue' %&gt;
  </code></pre>
  
  <p>"THIS IS VUE" is rendered fine, but I'm having this error.</p>
  
  <blockquote>
    <p>Error in mounted hook: "TypeError: The element or ID supplied is not
    valid. (videojs)"</p>
  </blockquote>
  
  <p>I have noticed <code>document.getElementById('videok')</code> is <code>null</code> at the time <code>mounted()</code> is triggered. If I do <code>vue create ""new project"</code> and paste the code of this component it works fine.</p>