Method userSignedOff

java/Chapter 8/Question8_7/UserManager.java:51–57

(String accountName)

	}
	
	public void userSignedOff(String accountName) {
		User user = usersByAccountName.get(accountName);
		if (user != null) {
			user.setStatus(new UserStatus(UserStatusType.Offline, ""));
			onlineUsers.remove(user.getId());
		}
	}	
}