add product use case implementation

Author: GabrielNat1

controller/product_controller.go

@@ -7,7 +7,9 @@ import (
 	"github.com/gin-gonic/gin"
 )
 
-type productController struct{}
+type productController struct {
+	productUseCase usecase.ProductUseCase
+}
 
 func NewProductController() *productController {
 	return &productController{}

usecase/product_usecase.go

@@ -0,0 +1,14 @@
+package usecase
+
+import "api-go/model"
+
+type ProductUseCase struct {
+}
+
+func NewProductuUseCase() *productUseCase {
+	return &productUseCase{}
+}
+
+func (pu *productUseCase) GetProducts([]model.Product, error) {
+	return []model.Product{}, nil
+}