add route for users
add show.html.erb
add show to UsersController
add FactoryGirl, user profile tests, and edit show.html.erb
edit config/environments/test.rb to speed up FactoryGirl
edit show.html.erb to add markup for gravitar
add styling for gravitar and username in custom.css.scss
add form to new.html.erb
add action in users controller that can handle signup failure (but not success)
Finish user signup
Add SSL in production
add tests for sign in links in spec/authentication_pages_spec.rb
add signin form to app/views/sessions/new.html.erb