         
         self.showDataForAlbum(currentAlbumIndex)
         
+        loadPreviousState()
         scroller.delegate = self
         reloadScroller()
+        
+        NSNotificationCenter.defaultCenter().addObserver(self, selector:"saveCurrentState", name: UIApplicationDidEnterBackgroundNotification, object: nil)
+    }
+    
+    deinit {
+        NSNotificationCenter.defaultCenter().removeObserver(self)
     }
 
 	override func didReceiveMemoryWarning() {

}

extension ViewController: HorizontalScrollerDelegate {
    
    func horizontalScrollerClickedViewAtIndex(scroller: HorizontalScroller, index: Int) {
        //1

        dataTable!.reloadData()
    }

    //MARK: Memento Pattern
    func saveCurrentState() {
        // When the user leaves the app and then comes back again, he wants it to be in the exact same state
        // he left it. In order to do this we need to save the currently displayed album.
        // Since it's only one piece of information we can use NSUserDefaults.
        NSUserDefaults.standardUserDefaults().setInteger(currentAlbumIndex, forKey: "currentAlbumIndex")
    }
    
    func loadPreviousState() {
        currentAlbumIndex = NSUserDefaults.standardUserDefaults().integerForKey("currentAlbumIndex")
        showDataForAlbum(currentAlbumIndex)
    }
}

extension ViewController: UITableViewDataSource {
