title: How to set optgroup select label in Vue.js?
body: <p>I'm trying to make a select group in Vue.</p>
  
  <p>Fiddle: <a href="https://jsfiddle.net/Tropicalista/vwjxc5dq/" rel="noreferrer">https://jsfiddle.net/Tropicalista/vwjxc5dq/</a></p>
  
  <p>I've tried this:</p>
  
  <pre><code>&lt;optgroup v-for="option in options" v-bind:label="option"&gt;
    &lt;option v-for="sub in option" v-bind:value="option.value"&gt;
     {{ sub.text }}
    &lt;/option&gt;
  &lt;/optgroup&gt;
  </code></pre>
  
  <p>My data:</p>
  
  <pre><code>data: {
    selected: 'A',
    options: {
      First: [
        { text: 'One', value: 'A' },
        { text: 'Two', value: 'B' }
      ],
      Second: [
       { text: 'Three', value: 'C' }
      ]
    }
  }
  </code></pre>