Ember cli, There is no route named contact error

I'm a newbie to Ember cli.I used latest version 2.6.2.I was struggling on the route.When i go to contacts page i got error like this Error: There is no route named contact.

My app/route.js

Router.map(function() {
  this.route('contacts', function() {
    this.route('show', { path: '/:contact_id' });
  });
});

My app/routes/contacts/index.js

export default Ember.Route.extend({
  model: function() {
    return this.store.findAll('contact');
  }
});

My app/templates/contacts/index.hbs

<ul>
  
    <li>
      
      ,
      
      
    </li>
  
    <li>No contacts found.</li>
  
</ul>

My app/models/contact.js

import DS from 'ember-data';

export default DS.Model.extend({
  firstName: DS.attr('string'),
  lastName: DS.attr('string'),
  email: DS.attr('string'),
  title: DS.attr('string'),
  createdAt: DS.attr('date'),
  updatedAt: DS.attr('date')   
});

Thanks for your help.