Email signup

Several folks have requested email signup.

Truthfully, I don't think I will have the time/energy to build this feature - auth is hard, and I like being able to delegate it to Google.

One potential solution suggested by a user is to use an email unlock, like Medium does. So you'd enter your email, it sends you a link, clicking on it creates your account and remembers you. You can also log in again with the same method. No passwords required.

But yeah, even with that, it seems like an awful lot of trouble for something most folks don't need. So, if anyone else wants to build it, I'm absolutely willing to accept PRs. Otherwise, it's not likely to be built.