DashboardController = AppController.extend({
    waitOn: function() {
        return this.subscribe('registrants');
    },
    data: {
        items: Registrants.find({})
    },
    onBeforeAction: function (pause) {
        AccountsTemplates.ensureSignedIn.call(this, pause);
    },
    onAfterAction: function () {
        Meta.setTitle('Registrants Dashboard');
    }
});

DashboardController = RouteController.extend({
  layoutTemplate: "dashboardLayout",
  waitOn: function() {
      return this.subscribe('registrants');
  },
  data: {
      items: Registrants.find({})
  },
  onBeforeAction: function (pause) {
      AccountsTemplates.ensureSignedIn.call(this, pause);
  },
  onAfterAction: function () {
      Meta.setTitle('Registrants Dashboard');
  }
});

Change lauout template