Fix Game and add: Observer

src/main/java/it/polimi/ingsw/gc14/Model/Game.java

@@ -17,7 +17,7 @@ import it.polimi.ingsw.gc14.Model.GamePackage.GameStages;
 import java.io.Serializable;
 import java.util.*;
 import java.util.stream.Collectors;
-
+import it.polimi.ingsw.gc14.Network.Observer;
 /**
  * Represents the main game model.
  * A Game object stores the players, the current state of the match,
@@ -25,6 +25,18 @@ import java.util.stream.Collectors;
  */
 public class Game implements Serializable {
 
+    private transient List<Observer> observers = new ArrayList<>(); // transient! non serializzare
+
+    public void addObserver(Observer observer) {
+        observers.add(observer);
+    }
+
+    private void notifyObservers() {
+        for (Observer o : observers) {
+            o.update(this);
+        }
+    }
+
     /**
      * The list of players participating in the game.
      */