How do I make a User login shutdown my box?

[Stuart Halliday]

I've got RedHat 8 on a Athlon box and I'd like a user logon to perform a shutdown of the box.

I was advised to do the following:
I've added a user called 'Sleep' and added this user to the root group via the User Manager program and made its login shell /sbin/shutdown in the /etc/passwd.

I've added in the users directory 2 lines in the .bashrc of:
PATH=$PATH:/sbin
export PATH
as I understand it this path isn't usually in a users path.

I added the user sleep to the /etc/shutdown.allow file as well.

But when I logon via the logon screen as user 'sleep', the picture goes black and then comes back again!

I tried pressing ctrl-alt-del at the logon screen but a wee box pops up asking for the root password to halt or reboot.

Any idea what else I need to do?

If any kind and knowledgeable person could guide me, I would welcome that. :-)

-- 
Stuart Halliday