Integrate django-scopes (#1319)

* Install django-scopes

* Fix tests.api

* Update tasks and cronjobs

* Fix remaining tests

* Remove unused import

* Fix tests after rebase

* Disable scopes for get_Events_with_any_permission

* Disable scopes for a management command

src/pretix/base/models/vouchers.py

@@ -8,6 +8,7 @@ from django.db.models import Q
 from django.utils.crypto import get_random_string
 from django.utils.timezone import now
 from django.utils.translation import pgettext_lazy, ugettext_lazy as _
+from django_scopes import ScopedManager
 
 from ..decimal import round_decimal
 from .base import LoggedModel
@@ -173,6 +174,8 @@ class Voucher(LoggedModel):
                     "convenience.")
     )
 
+    objects = ScopedManager(organizer='event__organizer')
+
     class Meta:
         verbose_name = _("Voucher")
         verbose_name_plural = _("Vouchers")