Ember - Getting started guide: DISPLAYING MODEL DATA - ember.js

Question

I'm going over Ember - Getting Started tutorial but I got stuck. Everything was fine until I got to Displaying-Model-Data section:
First, adding:
Todos.TodosRoute = Ember.Route.extend({
model: function () {
return Todos.Todo.find();
}
});
to the router.js file results in blank window, I found this post which helped returning the layout by adding the next line of code before the code above:
Todo.TodosController = Em.ArrayController.extend({});
Second, as I continue one step forward and try to replace the static index.html with handlebars to make it dynamic (by this code):
<ul id="todo-list">
{{#each controller}}
<li>
<input type="checkbox" class="toggle">
<label>{{title}}</label><button class="destroy"></button>
</li>
{{/each}}
</ul>
again my layout disappears and leaving me with a blank window.
I follow this tutorial step-by-step so don't know what could cause that.
(Found other relevant post but nothing was helpful).

Answer 1

After a few debug time, I found out what was the problem, but not exactly sure why.
I used handlebars.js (V 1.0.0) as published in the official site handlebarsjs.com (this is the one which also linked by the Ember Getting started guide in the dependencies section). After replacing it with the one in cloudflare the layout was brought back to life.
Hope it will help someone.
p.s: after this change the addition of
Todo.TodosController = Em.ArrayController.extend({});
is no longer relevant.