Ember: can't loop model in child controller (model ok in inspector)

i'm a beginner of Ember.js and i have some trouble with model/controller.

I have a structure like this:

router.js

Router.map(function() {

  this.route('search', function() {
    this.route('detail', { path: '/:search_id' });
    this.route('ranks', { path: '/:search_id/ranks' });
    this.route('tweets', { path: '/:search_id/tweets' });
  });
});

export default Router;

route/search.js

import Ember from 'ember';

export default Ember.Route.extend({
});

route/search/rank.js

export default Ember.Route.extend({

    model(params) {
        return this.get('store').findRecord('search', params.search_id);
    },

    setupController: function(controller, model) {
        controller.set('model', model);
    }
});

app/models/rank.js

export default DS.Model.extend({
    date: DS.attr(),
    tag: DS.attr('string'),
    rank: DS.attr('number'),
    freq: DS.attr('number'),

    search: DS.belongsTo('search')
});

app/models/search.js

export default DS.Model.extend({
    uniqueid: DS.attr('string'),
    idate: DS.attr('date'),
    fdate: DS.attr('date'),
    keywords: DS.attr(),

    ranks: DS.hasMany('rank')
});

app/controllers/search.js

export default Ember.Controller.extend({
});

app/controllers/search/rank.js

export default Ember.Controller.extend({

    mydata: Ember.computed('model', function() {

       this.get('model').forEach(function(item) {
          console.log(item);
       });
    });
});

This generate this error:

Uncaught TypeError: this.get(...).toArray is not a function(…)

I have read a lot of possible solution but i can't find the right one. Please can you help me? Thank you in advance.