override func viewDidLoad() {
  super.viewDidLoad()

  let editImage    = UIImage(named: "plus")!
  let searchImage  = UIImage(named: "search")!

  let editButton   = UIBarButtonItem(image: editImage,  style: .Plain, target: self, action: "didTapEditButton:")
  let searchButton = UIBarButtonItem(image: searchImage,  style: .Plain, target: self, action: "didTapSearchButton:")

  navigationItem.rightBarButtonItems = [editButton, searchButton]
}