nullable

packages/app/src/server/routes/apiv3/user-group.js

@@ -49,7 +49,7 @@ module.exports = (crowi) => {
     update: [
       body('name', 'Group name is required').trim().exists({ checkFalsy: true }),
       body('description', 'Group description must be a string').optional().isString(),
-      body('parentId', 'parentId must be a string').optional().isString(),
+      body('parentId', 'ParentId must be a string or null').optional({ nullable: true }).isString(),
       body('forceUpdateParents', 'forceUpdateParents must be a boolean').optional().isBoolean(),
     ],
     delete: [