[重要]完成局部模板，准备在测试文件中使用具名路由
[重要]完成具名路由的加入，准备开始简化RSpec代码
Merge branches 'filling-in-layout' and 'filling-in-layout' of github.com:lvyunyi/tutorial-ror into filling-in-layout

Conflicts:
	app/views/layouts/_footer.html.erb
	app/views/layouts/_header.html.erb