provide rsync support as another tar transport mechanism

[nanch]

create a new group called rsyncgroup

addgroup rsyncgroup

add this line to the createusers.pl script

usermod -a -G rsyncgroup USER

configure the sshd_config file at /etc/ssh/sshd_config to match the rsyncgroup users

alternatively, simply use the existing targroup and do not force sftp-internal when the user uses ssh login

[nanch]

instead of using rsync, serving as a duplicity target may be adequate for more robust client-side support.