assign is reset when an issue is updated

Hi,

We use kanban in your team with gitlab, great tool !

But we have a small problem : when we update an issue, the assignee parameter is changed to null and disappear form the user's board.

The configuration we use in docker container :

• Gitlab-CE : 8.14.1
• Kanban : 1.7.0
• Redis : 1.0.0

We have the problem in the previous version of Kanban (1.1.0) when we update to the last major version of gitlab.

After the update of kanban, the problem is still here :/

thanks for your help !