Fix bug with existing items

internal/postgres/items.go

@@ -42,7 +42,8 @@ func (s itemService) Item(id int, user *quartermaster.User) (*quartermaster.Item
 
 func (s itemService) AddItem(i *quartermaster.Item, l *quartermaster.Location, user *quartermaster.User) (*quartermaster.Item, error) {
 	var err error
-	if ib, _ := s.GetItemByBarcode(i.Barcode, user); ib == nil {
+	ib, _ := s.GetItemByBarcode(i.Barcode, user)
+	if ib == nil {
 		if i.Nutrition != nil {
 			i.Nutrition, err = NutritionService.AddNutrition(i.Nutrition)
 			if err != nil {
@@ -57,6 +58,8 @@ func (s itemService) AddItem(i *quartermaster.Item, l *quartermaster.Location, u
 		if err != nil {
 			return nil, err
 		}
+	} else {
+		i.ID = ib.ID
 	}
 	queryString := "INSERT INTO x_items_locations (item_id, location_id, count) VALUES ($1, $2, 1) ON CONFLICT (item_id, location_id) DO UPDATE SET count = x_items_locations.count + 1"
 	_, err = s.db.Exec(queryString, i.ID, l.ID)