title: vue-js-modal - "draggable" issue
body: <p>I am using <a href="https://github.com/euvl/vue-js-modal" rel="nofollow noreferrer">vue-js-modal</a> to display a draggable and resizable modal but I have an issue with "draggable" property.</p>
  
  <p>The modal is opening and all properties work properly except "draggable"; I can not drag the modal (seems to have no effect).
  This is how I set up the modal:</p>
  
  <pre><code>  &lt;modal class="vue-js-modal"
        name="modal-name"
        :draggable="true"
        :resizable="true"&gt;
  
      &lt;h1&gt;Modal Title&lt;/h1&gt;
  
    &lt;/modal&gt;
  </code></pre>
  
  <p>Can someone help me solving this issue?
  Thanks a lot</p>