Why can't I add user to group?

[Derek Broughton]

Dotan Cohen wrote:

> jaunty2 at laptop:~$ whoami
> jaunty2
> jaunty2 at laptop:~$ sudo usermod -a -G vboxusers jaunty2
> jaunty2 at laptop:~$ groups
> jaunty2 adm dialout cdrom plugdev lpadmin admin sambashare
> jaunty2 at laptop:~$

sudo -i jaunty2
groups

> 
> Why is that? I'm on Kubuntu 9.04.
> 

I'm pretty sure you have to effectively login to get the new groups.