title: How to get a child value in firebase with swift 3.0
body: <p>I want to display a string of "1.0" on an UITextField by reading the AppVersion Key from firebase
  My firebase JSON is simply the following</p>
  
  <pre><code>{
    "AppVersion" : "1.0"
  }
  </code></pre>
  
  <p>My swift code (swift 3.0)</p>
  
  <pre><code>override func viewDidLoad() {
      super.viewDidLoad()
  
      ref = FIRDatabase.database().reference().child("AppVersion")
      AppVersionLabel.text = ref.key
  }
  </code></pre>
  
  <p>The field display the word "AppVersion" instead of "1.0"</p>