title: how to sort array of objects according to sub property in ng2-order-pipe
body: <p>I am working on angular2 project which needs to sort array of objects,
  I am using ng2-order-pipe to sort array of objects here an example: </p>
  
  <pre><code>&lt;p *ngFor="let customer of customers | orderBy: 'Name'"&gt;{{ customer.Name}}&lt;/p&gt;
  </code></pre>
  
  <p>The Name attribute is a property in customer, the sort works properly,
  but what i want to do is sorting the array according to the customer.Group.Name.
  here is the documentation for ng2-order-pipe:
  <a href="https://www.npmjs.com/package/ng2-order-pipe" rel="nofollow noreferrer">https://www.npmjs.com/package/ng2-order-pipe</a></p>