Sign In Part I
 Changes to be committed:
	new file:   app/assets/javascripts/sessions.js.coffee
	modified:   app/assets/stylesheets/application.css
	renamed:    app/assets/stylesheets/users.css.scss -> app/assets/stylesheets/sessions.css.scss
	modified:   app/assets/stylesheets/users.css.scss
	new file:   app/controllers/sessions_controller.rb
	modified:   app/controllers/users_controller.rb
	new file:   app/helpers/sessions_helper.rb
	modified:   app/helpers/users_helper.rb
	modified:   app/models/user.rb
	modified:   app/views/layouts/_header.html.erb
	new file:   app/views/sessions/new.html.erb
	new file:   app/views/users/_form.html.erb
	new file:   app/views/users/edit.html.erb
	new file:   app/views/users/index.html.erb
	new file:   app/views/users/new.html.erb
	new file:   app/views/users/show.html.erb
	modified:   config/environments/production.rb
	modified:   config/routes.rb
	modified:   db/development.sqlite3
	new file:   db/migrate/20141223033957_add_username_to_users.rb
	modified:   db/schema.rb
	modified:   db/test.sqlite3
	modified:   log/development.log
	modified:   log/test.log
	new file:   spec/features/create_user_spec.rb
	new file:   spec/features/delete_user_spec.rb
	new file:   spec/features/edit_user_spec.rb
	new file:   spec/features/list_users_spec.rb
	new file:   spec/features/show_user_spec.rb
	new file:   spec/features/sign_in_spec.rb
	modified:   spec/support/attributes.rb