Adding an ssh or SFTP user for Vaultpress

I need to add a new user so wordpress Vaultpress can connect for backups. Thing is it needs read-write access.

Steps so far:

useradd vaultpressr passwd vaultpress usermod -m -d /path/to/website/public vaultpress

usermod -G www-data vaultpress

So now I have a user named vaultpress, who is part of the www-data group, who can SFTP in directly to the directory I need vaultpress to back up.

Except vaultpress can’t write to the directory. Vaultpress needs write ability to put files back.

I frankly don’t know what rights the various groups have, I was hoping that being part of the www-data group would give vaultpress the correct rights.

What to do next.

Thanks!