jquery_ujs async confirm

behaviors.js.coffee

$ ->
  $.rails.confirm = (message) ->
    answer = $.Deferred();

    modal = $ """
<div class="modal hide fade">
  <div class="modal-header">
    <button type="button" class="close" data-dismiss="modal" aria-hidden="true">&times;</button>
    <h3>Delete</h3>
  </div>
  <div class="modal-body">
    <p>#{message}</p>
  </div>
  <div class="modal-footer">
    <a href="#" class="btn" data-dismiss="modal">Close</a>
    <a href="#" class="btn btn-primary">Delete</a>
  </div>
</div>
    """

    modal.on 'click', 'a.btn-primary', (event) ->
      event.preventDefault()
      answer.resolve()

    modal.on 'hidden', ->
      answer.reject()

    modal.modal()

    answer.promise()