The old Gnome 2 User and Groups management tool has been turned off since Ubuntu 11.10 Oneiric. But it’s still avaiable in Ubuntu repository contained by package
So if you’re looking for this easy to use graphical method for modifying users’ group membership in Ubuntu 12.04, use following method to get it back.
In Ubuntu Software Center search and install
gnome-system-tools, then you can launch
Users and Groups in the Dash.
Or install it via
sudo apt-get install gnome-system-tools
Now, you get back this old Users Settings tool:
easily edit user advance settings: