title: Subclass PFUser in swift
body: <p>I wanna subclass the PFUser object in swift. 
  I also want to declare my own variables. The Parse documentation on subclassing do not cover PFUser at this point.</p>
  
  <p>Parse documentation on subclassing PFObject:</p>
  
  <pre><code>class Armor : PFObject, PFSubclassing {
      class func load() {
         self.registerSubclass()
      }
      class func parseClassName() -&gt; String! {
         return "Armor"
      }
  }
  </code></pre>