Add event-specific groups and signals

event/signals.py

@@ -0,0 +1,19 @@
+from django.dispatch import receiver
+from django.db.models.signals import post_save
+from event.models import Event
+from shared.models import GEGroup
+
+
+@receiver(post_save, sender=Event)
+def create_groups_for_event(sender, **kwargs):
+    event, created = kwargs["instance"], kwargs["created"]
+    if created:
+        GEGroup.objects.create(
+            name="orga",
+            event=event
+        )
+
+        GEGroup.objects.create(
+            name="participants",
+            event=event,
+        )

users/migrations/0001_initial.py

@@ -0,0 +1,25 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.3 on 2017-07-20 13:37
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    initial = True
+
+    dependencies = [
+        ('auth', '0008_alter_user_username_max_length'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='GEGroup',
+            fields=[
+                ('group_ptr', models.OneToOneField(auto_created=True, on_delete=django.db.models.deletion.CASCADE, parent_link=True, primary_key=True, serialize=False, to='auth.Group')),
+            ],
+            bases=('auth.group',),
+        ),
+    ]

users/models.py

@@ -1,2 +1,9 @@
 from django.db import models
-from django.contrib.auth.models import User
+from django.contrib.auth import get_user_model
+from django.contrib.auth.models import Group
+
+User = get_user_model()
+
+
+class GEGroup(Group):
+    pass