title: parsley.js how to trigger an error on a field with a custom error message
body: <p>It would be great if it was possible to do such thing as</p>
  
  <pre><code>$('input.specific-field').parsley('error', 'this is a custom error message');
  </code></pre>
  
  <p>...but I guess that isn't possible?</p>
  
  <p>How could I achive such thing?</p>