Fix common db relation insertion (#439)

* Fix common db relation insertion

* Fix and update changelog

* Update CHANGELOG.md

Co-authored-by: Stanislas <[email protected]>

---------

Co-authored-by: Stanislas <[email protected]>

Author: Lainow

CHANGELOG.md

@@ -13,6 +13,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ### Fixed
 
+- Fix relation (`CommonDBRelation`) insertion
 - Fix default entity insertion for a user
 - Fixed `SQL` error when creating new injection model
 - Fixed issue with missing dropdown options

inc/commoninjectionlib.class.php

@@ -1645,7 +1645,7 @@ private function effectiveAddOrUpdate($injectionClass, $item, $values, $add = tr
             //CommonDBRelation are managed separately, so related field should be ignored
             // Ex : User -> groups_id -> Group_User
             // groups_id should not be injected in User (field contains group name (string))
-            if ($option !== false && isset($option['displaytype']) && $option['displaytype'] == 'relation') {
+            if ($option !== false && isset($option['displaytype']) && $option['displaytype'] == 'relation' && !($item instanceof CommonDBRelation)) {
                 continue;
             }