title: React: how to notify parent for changes
body: <p>I'm trying to wrap bootstrap into components with integrated form validation.</p>
  
  <p>short:
  Let's say I have </p>
  
  <pre><code>&lt;Form&gt;
    &lt;FieldGroup&gt;
       &lt;Field rules={'required'}/&gt;
    &lt;/FieldGroup&gt;
  &lt;/Form&gt;
  </code></pre>
  
  <p>Once <code>Field</code> pases validation, how can I notify <code>FieldGroup</code> (parent node) to add a class?</p>
  
  <p>I created a simplified codepen version <a href="http://codepen.io/kossel/pen/eBdoXW" rel="noreferrer">here</a></p>
  
  <p>I would like depending on validation status, then change the state of FieldGroup So I can properly change the class name. (add <code>has-warning</code>  <code>has-danger</code> etc) and ultimately add class to the Form component.</p>