Do some basic input validation here to protect fools like me from ourselves:
- your README says `Use the signup button to create a new user and log in.`
- so I clicked the signup button
- 'Login failed, please try again EISDIR, read` -- wat?!?
- go to the code... oh! you wanted me to enter a username and password before clicking the signup affordance...
- ... here I thought I was going to get a signup form like any other website ;-)