add signin controller and stub signin view
add tests for signin page
implement invalid signin behavior
add test for flash message persisting too long
add user signin to sessions_controller
include sessions_helper in all controllers
add remember_token to user
add spec and impl for remember_token
implement session helpers for signin
add signout and profile links for signed in users
signin upon signup
add sign out
add spec user stays logged in
add spec for signin upon signup
show flash message on successful signin
move links for signed in users to dropdown menu
Merge pull request #8 from eToThePiIPower/sign-in-out

implement sign-in and sign-out