- Fix typo in rules path
- Fix capitalisation.
- `udevadm control --reload-rules` is unnecessary[1].
- `adduser` is Debian-specific, use the more portable `gpasswd`.
- No need to wait 10 seconds before re-inserting.
- After adding to group, user must re-login.
[1]: http://unix.stackexchange.com/a/39485/8250