nested routes for resources

made the routes nested for a resource in routes.js.handlebars
```javascript
  this.resource('people', function() {
    this.route('new_person', {path: 'new'});
    this.resource('person', {path: ':person_id'}, function() {
      this.route('edit_person', {path: 'edit'});
    });
  });
```
instead of:
```javascript
  this.resource('people');
  this.resource('person', {path: '/people/:person_id'});
  this.route('edit_personr', {path: '/people/:person_id/edit'});
  this.route('new_person', {path: '/people/new'});
```