title: Crash on pushViewController
body: <p>I'm trying to push a ViewController, but my app crashes every time.</p>
  
  <p>I'm using the UIImagePickerControllerDelegate to take a picture, and once the picture has been taken, this code runs:</p>
  
  <pre><code>func imagePickerController(picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [NSObject : AnyObject]) {
      let pickedImage = info[UIImagePickerControllerEditedImage] as! UIImage
  
      // Reset the cameraButton and Tabbar
      self.cameraButton.setImage(UIImage(named: "camera-button"), forState: .Normal)
      self.cameraButton.transform = CGAffineTransformMakeScale(1, 1)
      self.tabBarController?.tabBar.alpha = 1
  
      let realmImage = Image()
      realmImage.imagedata = UIImageJPEGRepresentation(pickedImage, 1.0)
  
      let birthmark = Birthmark()
      //birthmark.imagesArray = RLMArray()
      birthmark.imagesArray.addObject(realmImage)
      birthmark.bodyPart = Birthmark.Bodypart.LeftArm
  
      realm.beginWriteTransaction()
      realm.addObject(birthmark)
      realm.commitWriteTransaction()
  
      self.dismissViewControllerAnimated(true, completion: nil)
  
      let secondViewController = self.storyboard!.instantiateViewControllerWithIdentifier("ItemViewController") as! ItemViewController
      secondViewController.existingItem = birthmark
      navigationController!.presentViewController(secondViewController, animated: true, completion: nil)
  }
  </code></pre>
  
  <p>However, it always crashes on the last line:</p>
  
  <pre><code>navigationController!.presentViewController(secondViewController, animated: true, completion: nil)
  </code></pre>
  
  <p>XCode says: EXC_BREAKPOINT (code=1, subcode=0x100489474)</p>
  
  <p>Do you have any pointers as to what I'm doing wrong?</p>
  
  <p>Here's what my storyboard looks like:
  <img src="https://i.stack.imgur.com/4hOg0.png" alt="enter image description here"></p>
  
  <p>The stack trace:
  <img src="https://i.stack.imgur.com/u5kDx.png" alt="enter image description here"></p>