title: Formio.js get JSON text from builder method
body: <p>I read the docs about formio.js on github. But I can't see how to get json text after the form is build.</p>
  
  <p>Here's my code:</p>
  
  <pre><code>&lt;div id='builder'&gt;&lt;/div&gt;
  &lt;script type='text/javascript'&gt;
      var builder = Formio.builder(document.getElementById('builder'), {}, {});
  
      builder.then(function(form){
          form.on("change", function(e){
               console.log("Something changed on the form builder");
          });
      });
  &lt;/script&gt;
  </code></pre>
  
  <p>Now I want to take the json schema of the form to store in database.</p>