Feat(BE-36,37,38,39): finish master data management api

internal/entities/product_supplier.go

@@ -0,0 +1,9 @@
+package entities
+
+import "time"
+
+type ProductSupplier struct {
+	ProductID  uint      `gorm:"primaryKey"`
+	SupplierID uint      `gorm:"primaryKey"`
+	CreatedAt  time.Time `gorm:"autoCreateTime"`
+}