Fix (user could join a room twice) + Simon's request

Simon's request

ChatApp/src/ChatApp.java

@@ -9,15 +9,13 @@ public class ChatApp {
         Server server = new Server(6665);
         Client client = new Client(new InetSocketAddress("localhost", 6665));
 
-        client.SendCreateRoom("Room1");
-        client.RequestRoomList();
-        client.SendChatMessage("Hello");
+        client.SendCreateRoom("101");
 
         Scanner scanner = new Scanner(System.in);
         while (true) {
             String message = scanner.nextLine();
-            System.out.print("\033[1A"); // Déplacer le curseur une ligne vers le haut
-            System.out.print("\r\033[2K"); // Effacer la ligne entière
+            System.out.print("\033[1A");
+            System.out.print("\r\033[2K");
             System.out.flush();
             client.visitMessage(message);
         }

ChatApp/src/server/Server.java

@@ -63,7 +63,7 @@ public class Server implements PacketHandler {
 	}
 
 	public void joinRoom(String roomName, ServerConnexion connexion) throws SocketException {
-		if(roomNames.containsKey(roomName)) {
+		if(roomNames.containsKey(roomName) && !roomNames.get(roomName).contains(connexion)) {
 			roomNames.get(roomName).add(connexion);
 			return;
 		}