Nested routes model emberjs

I have following router:

App.Router.map(function () {
  this.resource('discount', {path: '/'}, function () {
    this.route('show', {path: '/show/:discount_id'})
});

here are routes:

App.CategoryRoute = Ember.Route.extend({
    model: function (params) {
        return this.store.find('discountCategory', params.category_id)
    }
})

App.CategoryIndexRoute = Ember.Route.extend({
    renderTemplate: function () {
        this.render('category/index'),
            this.render('modal', {
                outlet: 'modal',
            });
    },
    model: function () {
        var category = this.modelFor('category');
        return this.store.find('discount', {category_id: category.get('id')});
    },
});

App.CategoryShowRoute = Ember.Route.extend( {
    renderTemplate: function () {
        this.render('category_modal', {
            outlet: 'modal',
        });
        this.render('category/show');
    },
    model: function(params)
    {
        return this.store.find('discount',params.discount_id);
    }
});

and there is view:

<h1>Category/show</h1>
<div class="b-sales-coupons">
  {{#each discount in controllers.categoryIndex.model}}
    <a {{action 'showModal' discount}} href="#" data-toggle="modal" class="b-sales-coupons-element" data-target=".b-sales-modal">
    {{#discount-list-item discount=discount testAction='testAction'}}{{/discount-list-item}}
    </a>
  {{/each}}
</div>

When I am opening directly end point url: /categories/54e263084d6163051b010000/show/54e500a84169722aec000000

ember doesn't handle parent models in view from controllers.categoryIndex.model

In inspector there is only api call for this code:

this.store.find('discount',params.discount_id)

How to force child controller handle parent models?