private String signup(String[] msg) {
    	String ans =null;
        user.User user = forumSystem.signup(msg[1], msg[2], msg[3],msg[4], msg[5]);
        if (user!=null) {
        	this.user=user;
        	ans="SUCC_SIGNUP";
        }
        else ans="ERR_SIGNUP";
    	return ans;
    	
	}