def done(self):
# make sure the user doesn't already exist
u = User.by_name(self.username)
if u:
msg = 'That user already exists.'
self.render('signup-form.html', error_username=msg)
else:
u = User.register(self.username, self.password, self.email)
u.put()
self.login(u)
self.redirect('/')
