Edit Purchases Or User leads to 500

[Rebolon]

Hi,
i installed the project and follow the README.md, except that i use default doctrine param with the sqlite database.
The app is running on localhost:8001
If i try to edit one purchase then it fail and crash on 500

Go on a Purchase detail : http://localhost:8001/admin/?action=show&entity=Purchase&menuIndex=2&submenuIndex=-1&sortField=deliveryDate&sortDirection=DESC&page=1&referer=%252Fadmin%252F%253Faction%253Dlist%2526entity%253DPurchase%2526menuIndex%253D2%2526submenuIndex%253D-1%2526sortField%253DdeliveryDate%2526sortDirection%253DDESC%2526page%253D1&id=120180030803276001515076665

Then try to edit it : http://localhost:8001/admin/?entity=Purchase&referer=%252Fadmin%252F%253Faction%253Dlist%2526entity%253DPurchase%2526menuIndex%253D2%2526submenuIndex%253D-1%2526sortField%253DdeliveryDate%2526sortDirection%253DDESC%2526page%253D1&action=edit&id=120180030803276001515076665

Expect : the form to edit the purchase

Get : an HTTP 500

You can repeat this process with a User edit.