Feature Request: Allow unknown users while configuring others

[half-duplex]

I'm enjoying using this webdav service behind nginx, with nginx enforcing http basic auth.

I would like to expose a directory to all users who have successfully authenticated to nginx, but grant certain users more permissions or show them a different directory.

Current options are:

• Treat all users the same by configuring permissions, directory, etc in the top level of the config and leave users: empty (doesn't accomplish my goal)
• Explicitly configure every user in users (annoying to maintain)
• Run multiple instances of the webdav service and instruct "special" users to access a different domain or path to be routed to it (annoying to set up)

The most obvious way to implement this would be to allow allowUnknownUsers: true as a top-level config option, which would use users.<username> if present, or the top-level defaults otherwise.