public void sendPublicMessage (String sender, String message, Integer currentRoom) {
        for (Map.Entry<String, ClientHandler> user : activeUsers.entrySet()) {
            if (user.getValue().currentRoom.equals(currentRoom)) {
                PrintWriter out = user.getValue().out;
                out.println(sender + ": " + message);
                out.flush();
            }
        }
    }