New Twiddle

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  showModal: Ember.computed.alias('model.showModal')
});

models.user.js

import Model from 'ember-data/model';
import attr from 'ember-data/attr';
import { belongsTo, hasMany } from 'ember-data/relationships';

export default Model.extend({
  showModal: attr('boolean')
});

router.js

import Ember from 'ember';
import config from './config/environment';

const Router = Ember.Router.extend({
  location: 'none',
  rootURL: config.rootURL
});

Router.map(function() {
});

export default Router;

routes.application.js

import Ember from 'ember';

export default Ember.Route.extend({
  model(){
    return this.store.createRecord('user', {
      showModal: true
    });
  }
});

templates.application.hbs

<p>Application</p>
{{#if showModal}}
	<p>I'm a modal</p>
{{/if}}

twiddle.json

{
  "version": "0.13.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.16.2",
    "ember-template-compiler": "2.16.2",
    "ember-testing": "2.16.2"
  },
  "addons": {
    "ember-data": "2.16.3"
  }
}