title: Extend built-in User model to support more properties and behaviors in loopback
body: <p>I want a model to represent a profile in my <strong>loopback</strong> app. But, the built-in User model found in loopback only have the following properties</p>
  
  <ul>
  <li>username</li>
  <li>password</li>
  <li>realm</li>
  <li>emailVerified</li>
  </ul>
  
  <p>What is the best way to extend the <code>built-in User model</code> in order to insert more properties like <code>phone number</code>, <code>profile picture</code>, and the <code>likes</code>?</p>