add service files
add itemsService
add itemsService
loadItems
add ShopManager to index.html
change type to category
add IndexCtrl
update itemsService
change ng-click
update item.js
add addToCart function in itemsService
update cart.js and cart.html with ng-repeat
update add to cart function
add lodash to package.json
change cartList
update itemCtrl
change cartItemService
add categoryManager.html
add goodsInformationManager.html
add two html pages