I have a web server, which is running under www-data user and group.
Also I have a ftp server, where is a virtual user with id 30000 and group id 30000 (which is also virtual).
There is running a Joomla.
Now a problem is, when user uploads data over ftp and when some module is installed over web, it has different owners and user is not able to change those files uploaded over web interface.
I have a proftpd with SQL.
There is table ftp_users and ftp_groups where are virtual users.
One option maybe is to assing www-data to the user, but I don't know how to assing www-data group to the virtual user.