title: Parse PFUser Subclass Sign Up using Swift Best Practice
body: <p>I have just downloaded and experimented with Parse. </p>
  
  <p>Everything works as expected, but I have a question regarding a good subclassing design.</p>
  
  <p>The standard PFUser has THREE fields by default. </p>
  
  <ol>
  <li>username</li>
  <li>emailAddress</li>
  <li>password</li>
  </ol>
  
  <p>I would like to add a few more "column" to the User table. Those are:</p>
  
  <ol>
  <li>firstName</li>
  <li>lastName</li>
  <li>phone (Optional)</li>
  <li>profilePicture</li>
  </ol>
  
  <p>Below is my subclass design, but I am not sure if this is the way one might want to subclass their PFUser.  </p>
  
  <pre><code>import UIKit
  
  class GPUser: PFUser, PFSubclassing {
      var firstName: String? {
          didSet {
              self["firstName"] = firstName;
          }
      }
      var lastName: String? {
          didSet {
              self["lastName"] = lastName;
          }
      }
      var phone: String? {
          didSet {
              self["phone"] = phone;
          }
      }
      var profilePicture: PFFile? {
          didSet {
              self["profilePicture"] = profilePicture;
          }
      }
  }
  </code></pre>
  
  <p>Questions:</p>
  
  <ol>
  <li><p>I am wondering what is the best approach to subclass a PFUser (in order to add columns to it) and of course the best design possible. Do you have any design in mind?        </p></li>
  <li><p>should we override the init method and instantiate all of the variables (firstName, lastName, phone, etc) so that the optional fields column get created on signUp?  </p></li>
  <li><p>Should I get rid of those didSets blocks? If yes, could you suggest on a better design?  </p></li>
  </ol>