Added voucher data model [backwards incompatible]

src/pretix/base/models/vouchers.py

@@ -0,0 +1,68 @@
+from django.db import models
+from django.utils.translation import ugettext_lazy as _
+
+from .event import Event
+from .items import Item
+from .orders import CartPosition, OrderPosition
+
+
+class Voucher(models.Model):
+    event = models.ForeignKey(
+        Event,
+        on_delete=models.CASCADE,
+        related_name="vouchers",
+        verbose_name=_("Event"),
+    )
+    code = models.CharField(
+        verbose_name=_("Voucher code"),
+        max_length=255
+    )
+    valid_until = models.DateTimeField(
+        blank=True, null=True,
+        verbose_name=_("Valid until")
+    )
+    block_quota = models.BooleanField(
+        default=False,
+        verbose_name=_("Reserve ticket from quota"),
+        help_text=_(
+            "If activated, this voucher will be substracted from the affected product\'s quotas, such that it is "
+            "guaranteed that anyone with this voucher code does receive a ticket."
+        )
+    )
+    allow_ignore_quota = models.BooleanField(
+        default=False,
+        verbose_name=_("Allow to bypass quota"),
+        help_text=_(
+            "If activated, a holder of this voucher code can buy tickets, even if there are none left."
+        )
+    )
+    price = models.DecimalField(
+        verbose_name=_("Set product price to"),
+        decimal_places=2, max_digits=10, null=True, blank=True
+    )
+    item = models.ManyToManyField(
+        Item, related_name='vouchers',
+        verbose_name=_("Product"),
+        help_text=_(
+            "This product is added to the user's cart if the voucher is redeemed."
+        )
+    )
+
+    class Meta:
+        verbose_name = _("Voucher")
+        verbose_name_plural = _("Vouchers")
+        unique_together = (("event", "code"),)
+
+    def save(self, *args, **kwargs):
+        self.code = self.code.upper()
+        super().save(*args, **kwargs)
+
+    def is_ordered(self) -> int:
+        return OrderPosition.objects.current.filter(
+            voucher=self.voucher
+        ).exists()
+
+    def is_in_cart(self) -> int:
+        return CartPosition.objects.current.filter(
+            voucher=self.voucher
+        ).count()