implemented closing button functionality

src/main/java/Gui/ActionHandler.java

@@ -9,6 +9,11 @@ public class ActionHandler implements ActionListener {
 		if (e.getSource() == gui.CloseBtn) {
 			System.exit(0);
 		}
+		
+		if (e.getSource() == GameGui.ClosingBtn) {
+			System.exit(0);
+		}
+		
 	}
 
 }

src/main/java/Gui/GameGui.java

@@ -144,5 +144,6 @@ GridBagConstraints gbc;
 		LosingPanel.add(ClosingBtn,gbc);
 		
 		RestartBtn.addActionListener(new RestartGame());
+		ClosingBtn.addActionListener(new ActionHandler());
 	}
 }