title: Props not linking with parent instance data
body: <p>I have a "Product" component. The data from parent isn't passing to child. It stays set to default value entered from main template. Depending on premium value, shipping is free or costs 2,69.</p>
  
  <p>I tried to understand using VueMastery introduction videos.. But i'm still struggling, can you please explain clear about what's the problem?</p>
  
  <pre><code>var app = new Vue({
      el: '#app',
      data: {
          premium: false // Changing the value here doesn't make any change
      }
  })
  </code></pre>
  
  <pre><code>Vue.component('product', {
      props: {
          premium: {
              type: Boolean,
              required: true
          }
      }, 
      template: ``,
      data() {},
      computed: {
          shipping() {
              if(this.premium) {
                  return "Free";
              }
              return 2.69;
          }
      }
  }
  </code></pre>
  
  <pre><code>&lt;div id="app"&gt;
      &lt;product :premium="true"&gt;&lt;/product&gt; // Changing this, it works..
  &lt;/div
  </code></pre>
  
  <p>Thanks in advance.</p>