tweak environment config
Installed and configured Devise
	but didn't generate a devisable model yet.
Generated devisable User
	with all Devise modules enabled.
Generated customizable Devise views, and converted them from ERB to Slim
Removed Devise; prepare to build authentication from scratch.
	Devise will not meet my needs. I think I have pretty standard expectations
	for authentication, but each small adjustment requires me to rewrite
	a portion of Devise's functionality, and it's reached a point where
	I'm better off building my own system from scratch.
	I'm starting that process now.
Users and sessions
	- Users can register a new account, view and edit their profile
	- Users can sign in, sign out, and their session times out after an hour.
	- if their session times out while in an access controlled area,
		they're redirected to the signin page. After they sign in, they're redirected
		back to the original page they were on.
	- AJAX requests are not redirected as described above.
		Instead, a JS alert tells the user that they need to sign in again.
	- Users cannot view or edit other users' profiles. If they try to, they're
		directed to the signin page.
Full authentication complete
	- lock and unlock account
	- password reset
	- track login information like last login time and IP
	- complete specs for the authentication area
Refactor flash messages to make controllers more readable
	Flash messages are stored in /config/flash_messages.yml now.
	An application controller method allows any controller to
	set the flash based on its label.
	This makes both controllers and tests more legible and a bit DRYer.