修改了标题，提交，更新按钮
更换了侧栏图标
滚动到底部可以快速回到顶部
删除冗余文件
增加了spec测试
增加了路由测试
修改了大部分页面
产品管理页面
产品修改页面
产品添加页面
product.css
对于products_controller.rb页面的修改
Merge branch '产品管理页面' of https://github.com/agilehu/PadAdmin-Github into 产品管理页面

Conflicts:
	app/assets/stylesheets/products.css.scss
	app/views/products/_form.html.erb
	app/views/products/edit.html.erb
	app/views/products/index.html.erb
	app/views/products/new.html.erb
	app/views/products/show.html.erb