title: iOS - Firebase error: Use of unresolved identifier FIRApp running supplied code
body: <p>When trying to configure XCode to work with Firebase 3, using the code in the setup docs gives me an error:</p>
  
  <p><a href="https://firebase.google.com/docs/ios/setup#add_the_sdk">https://firebase.google.com/docs/ios/setup#add_the_sdk</a></p>
  
  <pre><code>import UIKit
  import Contacts
  import Firebase
  
  @UIApplicationMain
  class AppDelegate: UIResponder, UIApplicationDelegate {
  
      var window: UIWindow?
  
      //contacts
      var contactStore = CNContactStore()
  
  
      func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -&gt; Bool {
          FIRApp.configure() &lt;-- Use of unresolved identifier 'FIRApp'
          // Override point for customization after application launch.
          return true
      }
  </code></pre>