Creating multiple to-dos with Ember example

I'm trying to create multiple to-do lists using Ember example. I tried to extend it using this, but I'm having some trouble blending into the Ember to-do example.

I have TodosRoute and TodosIndexRoute making the to-do list work, and I'm creating model 'stack' to group individual todos.

Here's my router.js

Todos.Router.map(function() {

  this.resource('todos', { path: '/todos' }, function () {
        // additional child routes will go here later
        this.route('active');
        this.route('completed');
    });
  this.resource('stacks', {path: '/'}, function(){
    this.route('stack', {path: '/stack/:stack_id'});
  });
});




Todos.TodosRoute = Ember.Route.extend({
  model: function() {
    return this.store.find('todo');
  }
});




Todos.TodosIndexRoute = Ember.Route.extend({
  model: function() {
    return this.modelFor('todos');
  }
});




Todos.StacksRoute = Ember.Route.extend({
  model: function() {
    return this.store.find('stack');
  }
});



Todos.StacksStackRoute = Ember.Route.extend({
  model: function(params){
    return this.store.find('stack', params.list_id);
  }
});



Todos.TodosActiveRoute = Ember.Route.extend({
  model: function(){
    return this.store.filter('todo', function(todo) {
      return !todo.get('isCompleted');
    });
  },
  renderTemplate: function(controller) {
    this.render('todos/index', {controller: controller});
  }
});




Todos.TodosCompletedRoute = Ember.Route.extend({
  model: function() {
    return this.store.filter('todo', function(todo) {
      return todo.get('isCompleted');
    });
  },
  renderTemplate: function(controller) {
    this.render('todos/index', {controller: controller});
  }
});

And my stacks_controller.js

Todos.StacksController = Ember.ArrayController.extend({
    actions: {
        createNewStack: function() {
            var stack = this.store.createRecord('stack');
            var _id = stack.get('id');
            stack.set('title', 'new stack ' + _id);
            stack.save();
        }
    }
});

Model.js

Todos.Todo = DS.Model.extend({
  title: DS.attr('string'),
  isCompleted: DS.attr('boolean')
});



Todos.Stack = DS.Model.extend({
  title: DS.attr('string'),
  todos: DS.hasMany('todo')
}); 

And then some bits from template

<button {{action "createNewStack"}} class="btn btn-default navbar-btn navbar-left">+ stack</button></a>

<section id ="list">
  {{#each}}
    {{#link-to 'stack' this}}
    <li>{{title}}</li>
    {{/link-to}}
  {{/each}}
</section>

It would be great if you could help me think about how I can structure the stack-todos relationship. I thought about making todos a child route of stack (and todo is already a child route of todos), then it would be a three layered relationship, which I don't know how to build.

Thanks a ton!