Add route to get a particular book

internal/myvalidator/myvalidator.go

@@ -25,7 +25,7 @@ func ValidateId(db *gorm.DB, id uint, value any) error {
 	}
 	if errors.Is(result.Error, gorm.ErrRecordNotFound) {
 		return HttpError{
-			StatusCode: http.StatusBadRequest,
+			StatusCode: http.StatusNotFound,
 			Err:        fmt.Errorf("Id %d could not be found for model %s", id, value),
 		}
 	} else {