flow: user signs up, with email. their activation email is redirected to me. if they look good, i forward that email.
unfortunately gitea doesn't notify me of user applications. so new users will want to contact me out-of-band.
notably, this avoids the problem where `co<tab>` can't auto-complete the trailing slash. `cf<tab>` autocompletes to `cfg/` in the same number of keystrokes :-)
