Sign Up Part I
 Changes to be committed:
	new file:   app/assets/javascripts/sessions.js.coffee
	new file:   app/assets/stylesheets/sessions.css.scss
	new file:   app/controllers/sessions_controller.rb
	new file:   app/helpers/sessions_helper.rb
	modified:   app/views/layouts/_header.html.erb
	new file:   app/views/sessions/new.html.erb
	modified:   config/routes.rb
	new file:   spec/controllers/sessions_controller_spec.rb
	new file:   spec/helpers/sessions_helper_spec.rb