add simplecov for testing
add controllers for users
add controller (and related asset/spec files) for Sessions
consider adding SASS (especially afer a successful heroku deployment (initial round? or real round?))
add nav li styling to application.css
add create and destroy routes for SessionsController
set stage for next commit
validate password match for user model
add nav view
add users routes and login/logout/signup routes
link _nav partial to application (master) layout
add error messages display to application (master) layout