add users to already deployed ftp server charm

[Vasiliy Tolstov]

Hi! I need to able add/del ftp users (login:passwd format) on already
deployed ftp server unit.

What is the idiomatic right way to do this? I'm already have relation
to establish connections to needed services, but also i need to
add/del users by hand. For example i have sinle unit ftp server and
need to create 10-20 users with passwords and may be different home
dirs. As i see charm does not have dictionary or list types.

-- 
Vasiliy Tolstov,
e-mail: v.tolstov at selfip.ru