Ember 1.0-rc3 Handlebars reloading. Slightly modified from https://github.com/discourse/discourse/blob/master/app/assets/javascripts/discourse/components/development.js

gistfile1.js

// https://github.com/discourse/discourse/blob/master/app/assets/javascripts/discourse/components/development.js
// Updated for Ember 1.0-rc3 
Ember.reloadTemplate = function(templateName) {
  Ember.TEMPLATES.empty = Handlebars.compile("<div></div>");
  $.getScript("/assets/templates/" + templateName, function(data, textStatus, jqXhr) {
    delete Ember.Container.defaultContainer._container.cache.dict["template:" + templateName]
    $.each(Ember.View.views, function() {
      var _this = this;
      if (this.get('templateName') === templateName) {
        this.set('templateName', 'empty');
        this.rerender();
        return Em.run.next(function() {
          _this.set('templateName', templateName);
          return _this.rerender();
        });
      }
    });
  });
};