title: Watching computed properties
body: <p>I have a component with the following hash </p>
  
  <pre><code>{ 
    computed: { 
      isUserID: { 
        get: function(){
           return this.userId? 
        } 
    }
  }
  </code></pre>
  
  <p>Should I be watching <code>isUserID</code> or <code>userId</code> for changes? Can you watch computed properties?</p>