小编Why*_*Why的帖子

[user@localhost ~]$ su -
Password: 
Last login: ...
[root@localhost ~]# usermod -aG wheel user
[root@localhost ~]# exit
logout
[user@localhost ~]$ sudo echo 123
[sudo] password for user: 
user is not in the sudoers file.  This incident will be reported.

我做错了什么？