title: iOS custom keyboard with storyboard
body: <p>I'm trying to make a simple iOS custom keyboard extension using Swift. The default UIView wasn't meeting my needs, so I read on <a href="https://stackoverflow.com/questions/25979693/ios8-custom-keyboard-using-storyboards">this</a> SO question that I could use a storyboard with the <code>NSExtensionMainStoryboard</code> property in <code>info.plist</code>.</p>
  
  <p>Unfortunately every time I open my keyboard, I get the following errors</p>
  
  <pre><code>2016-01-18 18:02:56.350 Kappa Keyboard[44790:2959180] Failed to inherit CoreMedia permissions from 44787: (null)
  2016-01-18 18:02:56.368 Kappa Keyboard[44790:2959138] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[__NSArrayM insertObject:atIndex:]: object cannot be nil'
  *** First throw call stack:
  (
      0   CoreFoundation                      0x002f1746 __exceptionPreprocess + 182
      1   libobjc.A.dylib                     0x01d32a97 objc_exception_throw + 44
      2   CoreFoundation                      0x001a6ce1 -[__NSArrayM insertObject:atIndex:] + 881
      3   CoreFoundation                      0x001a6941 -[__NSArrayM addObject:] + 65
      4   UIKit                               0x00c7d0bd -[UIViewController _addChildViewController:performHierarchyCheck:notifyWillMove:] + 417
      5   UIKit                               0x00c968aa -[UIViewController(UIContainerViewControllerProtectedMethods) addChildViewController:] + 78
      6   UIKit                               0x01206db8 -[_UIViewServiceViewControllerOperator __createViewController:withContextToken:fbsDisplays:appearanceSerializedRepresentations:legacyAppearance:traitCollection:initialInterfaceOrientation:hostAccessibilityServerPort:canShowTextServices:replyHandler:] + 2702
  </code></pre>
  
  <p>The stack trace continues on, but that's the gist of it.</p>
  
  <p>Here's all I've done (I tried this in a clean project).</p>
  
  <ol>
  <li>Create container app</li>
  <li>Create Keyboard target</li>
  <li>Add Main.storyboard</li>
  <li>Add <code>NSExtension.NSExtensionMainStoryboard: Main</code> to info.plist</li>
  <li>Set <code>Main.storyboard</code>'s custom class to the default <code>KeyboardViewController</code></li>
  </ol>
  
  <p>Any idea what I'm missing?</p>