async photo uploading

form.html

<script type="text/javascript">
// You'll probably have to call this from $(document).ready because it requires the DOM to be loaded.
function bindToForm(){
  $("#upload-photo-form").fileupload({
    dataType: 'json',
    progress: function() { 
      // Indicate that the upload has begun 
    },
    done: function(e, data) {
      // use data.id, data.name, and data.url to display the photo
    }
  });
};
</script>
  
<form action="events/upload_photo" id="upload-photo-form">
  <input name="utf8" type="hidden" value="✓">
  <input name="authenticity_token" type="hidden" value="<%= form_authenticity_token %>">
  <input name="event_id" type="hidden" value="<%= @event.id %>">
  <input name="file" type="file">
</form>