Fixed typo

ref #49

src/controllers/PermissionController.ts

@@ -79,7 +79,7 @@ export class PermissionController {
     @ResponseSchema(PrincipalNotFoundError, { statusCode: 404 })
     @ResponseSchema(PermissionIdsNotMatchingError, { statusCode: 406 })
     @ResponseSchema(PermissionNeedsPrincipalError, { statusCode: 406 })
-    @OpenAPI({ description: "Update a permission object. <br> If updateing the permission object would result in duplicate permission (same target, action and principal) this permission will get deleted and the existing permission will be returned. <br> Please remember that id's can't be changed." })
+    @OpenAPI({ description: "Update a permission object. <br> If updateing the permission object would result in duplicate permission (same target, action and principal) this permission will get deleted and the existing permission will be returned. <br> Please remember that ids can't be changed." })
     async put(@Param('id') id: number, @Body({ validate: true }) permission: UpdatePermission) {
         let oldPermission = await this.permissionRepository.findOne({ id: id }, { relations: ['principal'] });