Manual SSH accounts

[raphael]

What I'm saying is that the group www-data shouldn't be used at all for domain users.
If you want to create a user who has access to a same group, just use --groups GROUP1,GROUP2 when calling useradd and passing a list of extra groups, or, if you want it to belong only to that group, use --gid GROUP
for more information check man useradd(8)