Created login and logout

Added sessions to login and logout and basic session skeleton to use on each page.
Added create account functionality
Created deck.rb controller and moved get /deck

Also added My Stats link
Merge pull request #5 from ameliapadua/Login-CreateAccount-Logout

Login create account logout
Merge branch 'master' into gameplay

Conflicts:
	flash-cards/app/controllers/deck.rb
	flash-cards/app/views/deck/index.erb