Fixes #110 by adding a 'sign out' link for authenticated users.
Adds platform and region fields to the users table.
Adds new platform and region select menus on the post-signup form, in addition to the email field that was already there.
Styles the post-signup form.
Adds a new Settings page where the user can change their email, platform, and region.
Uses the Lootbox unofficial Overwatch API to get the user's avatar from the game. The region and platform are used to look up the user's profile, which is how we get the avatar.
This branch:
platformandregionfields to theuserstable./cc @RobThePM