bug fix

service/goods/orders.go

 	"github.com/yl10/kit/guid"
 )
 
-var mtx sync.Mutex
+var mtx *sync.Mutex
 
 // Orders 下单
 func (s *GoodsServ) Orders(
 
 	return order, nil
 }
+
+func init() {
+	mtx = new(sync.Mutex)
+}