feat: add stock movement on backend

backend/main.go

@@ -67,6 +67,8 @@ func main() {
 			admin.GET("/orders", handlers.GetAllOrders)
 			admin.PATCH("/orders/:id", handlers.UpdateOrderStatus)
 			admin.PATCH("/items/:id/avatar", handlers.UploadItemAvatar)
+			admin.POST("/stock/in", handlers.StockIn)
+			admin.POST("/stock/out", handlers.StockOut)
 		}
 	}