Implement payment backends and interaction

Advances #3 (closed)

aleksis/apps/tezor/models/invoice.py

 from django.contrib.contenttypes.fields import GenericForeignKey
 from django.contrib.contenttypes.models import ContentType
 from django.db import models
+from django.shortcuts import reverse
 from django.utils.translation import gettext_lazy as _
 
 from djmoney.models.fields import CurrencyField, MoneyField
@@ -77,3 +78,9 @@ class Invoice(BasePayment, PureDjangoModel):
         })
 
         return TotalsTable(values)
+
+    def get_success_url(self):
+        return reverse("payment_details", kwargs={"token": self.token})
+
+    def get_failure_url(self):
+        return reverse("payment_details", kwargs={"token": self.token})