There is a script adduserperm available to set up who can access
adduser. It might make sense to have a user/group guest who allows
an online registration like on our site. In that case use adduserperm
to allow that user to generate new users.

adduser allows to generate a file /usr/local/sbin/adduser.local with
local commands to execute on each registration of a user.

Christoph Lameter, <clameter@debian.org>
