Open
Description
The current behavior when a user signs up with just an email address is that the email address is slugified to a username. This is not ideal.
The signup process should allow both username and email at the same time.
In addition, it seems that if a user links their Github account after creating an account by email, it will create a new account if the account names are not the same. Instead, the Github account should link with the pre-existing session.