first commit
add some gems, to use slim
change to slim
set root_path
fix migrate:failed
Merge branch 'auth/twitter'

Conflicts:
	app/controllers/application_controller.rb
	app/controllers/base_controller.rb
	app/controllers/sessions_controller.rb
	app/models/user.rb
	app/views/layouts/application.html.slim
	config/application.rb
	config/initializers/devise.rb
	config/routes.rb
	config/settings.yml
	db/schema.rb
	db/seeds.rb
	spec/factories/users.rb
test4