         }
     }
     
+    func setupObserver() {
+        NSNotificationCenter.defaultCenter().addObserver(
+            self,
+            selector: Selector("applicationDidBecomeActive"),
+            name: UIApplicationDidBecomeActiveNotification,
+            object: nil
+        )
+        NSNotificationCenter.defaultCenter().addObserver(
+            self,
+            selector: Selector("applicationDidEnterBackground"),
+            name: UIApplicationDidEnterBackgroundNotification,
+            object: nil
+        )
+    }
+    
+    // MARK: - Observer
+    
+    func applicationDidBecomeActive() {
+        self.updatedAt = nil
+        self.locationManager.startUpdatingLocation()
+    }
+    
+    func applicationDidEnterBackground() {
+        self.locationManager.stopUpdatingLocation()
+    }
     
     // MARK: - CLLocationManagerDelegate
     

        return UIImage(named: name!)
    }
    
}

    override func viewDidLoad() {
        super.viewDidLoad()
        self.setup()
        self.setupObserver()
        
        self.locationManager.startUpdatingLocation()
    }
    
    override func viewWillDisappear(animated: Bool) {
        super.viewDidDisappear(animated)
        self.locationManager.stopUpdatingLocation()
    }
    
