add bootstrap's javascript file
add sessions controller, sign up page, and first tests for sign up page
more testing on the sign up page
add migration remember_token to users
update user with remember_token methods and add tests for them
add sessions_helper methods for handling sign_in, current_user, and sign_out.
clean up tests and made all of them pass
update header view to change links when user is signned in
finish sign in session tests
clean up extra files