override func viewDidLoad() {
    super.viewDidLoad()
    addUIElements()
}

// MARK: - UI functions

private func addUIElements() {
    view.addSubview(headerView)

    let lifelineController = StoryboardManager.lifeLineStoryboard.instantiateViewControllerWithIdentifier("LifeLineCollectionViewController") as! LifeLineCollectionViewController
    addChildViewController(lifelineController)
    lifelineController.view.frame = CGRect(x: 0, y: headerView.frame.height, width: headerView.frame.width, height: 100)
    view.addSubview(lifelineController.view)
    lifelineController.didMoveToParentViewController(self)
}