Minor bugfix

dmp-backend/web/src/main/java/eu/eudat/logic/managers/InvitationsManager.java

@@ -43,6 +43,7 @@ public class InvitationsManager {
                 UserAssociation userAssociation = new UserAssociation();
                 userAssociation.setFirstUser(principalUser);
                 userAssociation.setSecondUser(userInfo);
+                apiContext.getOperationsContext().getDatabaseRepository().getUserAssociationDao().createOrUpdate(userAssociation);
             }
         }
         DMP dataManagementPlan = apiContext.getOperationsContext().getDatabaseRepository().getDmpDao().find(invitation.getDataManagementPlan());