public void setUsers(String strategy) throws Exception {
       if(strategy.equals("userToUser")){
           users.put(1, new User(1, "human", "white"));
           users.put(2, new User(2, "human", "black"));
       } else if(strategy.equals("userToRobot")){
           users.put(1, new User(1, "human", "white"));
           users.put(2, new User(2, "robot", "black"));
       } else if(strategy.equals("robotToRobot")){
           users.put(1, new User(1, "robot", "white"));
           users.put(2, new User(2, "robot", "black"));
       }
       setCurrentUser(1);
    }