One thing that sometimes happens is that users will try to log in using their

e-mail address instead of their username, and then get confused when it doesn't

work. This is exacerbated by the fact that our sessions last a long time, so

it's often been a very long time since users had to log in.
This change makes it so that if a user logs in, and the username isn't found,

it will try to look up their user by e-mail address.

Logged in to my devserver using both my username and my e-mail address.