title: AppDelegate file not working
body: <p>Hi im creating my first app with Xcode and I've imported loads of stuff into my project so I can have a tab navigation system and im getting the following errors:</p>
  
  <p><img src="https://i.stack.imgur.com/yJNsx.jpg" alt="https://pbs.twimg.com/media/BObuzzcCIAII4Ao.jpg:large"></p>
  
  <p>error:</p>
  
  <pre><code>Undefined symbols for architecture i386:
    "_OBJC_CLASS_$_AltonTowersCode", referenced from:
        objc-class-ref in AppDelegate.o
    "_OBJC_CLASS_$_ChessingtonCode", referenced from:
        objc-class-ref in AppDelegate.o
    "_OBJC_CLASS_$_LegolandCode", referenced from:
        objc-class-ref in AppDelegate.o
    "_OBJC_CLASS_$_ThorpeParkCode", referenced from:
        objc-class-ref in AppDelegate.o
  ld: symbol(s) not found for architecture i386
  clang: error: linker command failed with exit code 1 (use -v to see invocation)
  </code></pre>