Refs #314 -- Read-only REST API (#513)

* initial commit

* API auth

* Hierarchical URLs

* Add session auth

* Strong hierarchy

* Add filters

* Add i18n fields, questions

* More viewsets and serializers

* Ticket download

* Add OrderPosition serializer

* View-level permissions

* More tests

* More tests

* Add basic API docs

* Add REST API to docs frontpage

* Tests for order endpoints

* Add invoice tests

* Voucher and waitinglist tests

* Doc draft

* order docs

* Docs on all viewsets

* Disable DRF docs, style sphinx, style browsable API

* Fix tests

* deprecated imports

* Test foo

* Attendee names

* Fix migration problems

* Remove browsable API, plugin integration

* Doc fixes

src/pretix/base/models/invoices.py

@@ -1,8 +1,8 @@
 import string
-from datetime import date
 from decimal import Decimal
 
 from django.db import DatabaseError, models, transaction
+from django.utils import timezone
 from django.utils.crypto import get_random_string
 from django.utils.functional import cached_property
 
@@ -15,6 +15,10 @@ def invoice_filename(instance, filename: str) -> str:
     )
 
 
+def today():
+    return timezone.now().date()
+
+
 class Invoice(models.Model):
     """
     Represents an invoice that is issued because of an order. Because invoices are legally required
@@ -56,7 +60,7 @@ class Invoice(models.Model):
     refers = models.ForeignKey('Invoice', related_name='refered', null=True, blank=True)
     invoice_from = models.TextField()
     invoice_to = models.TextField()
-    date = models.DateField(default=date.today)
+    date = models.DateField(default=today)
     locale = models.CharField(max_length=50, default='en')
     introductory_text = models.TextField(blank=True)
     additional_text = models.TextField(blank=True)