First things to implement a event change log

dav_events/migrations/0034_eventchange.py

@@ -0,0 +1,35 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.29 on 2020-09-29 10:11
+from __future__ import unicode_literals
+
+import dav_events.models.eventchange
+import dav_events.roles
+from django.conf import settings
+from django.db import migrations, models
+import django.db.models.deletion
+import django.utils.timezone
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+        ('dav_events', '0033_auto_20200925_1543'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='EventChange',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('timestamp', models.DateTimeField(default=django.utils.timezone.now)),
+                ('operation', models.CharField(choices=[('update', 'update')], max_length=20)),
+                ('content', models.TextField()),
+                ('event', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='changes', to='dav_events.Event')),
+                ('user', models.ForeignKey(default=dav_events.models.eventchange.get_system_user_id, on_delete=models.SET(dav_events.roles.get_ghost_user), related_name='+', to=settings.AUTH_USER_MODEL)),
+            ],
+            options={
+                'ordering': ['event', 'timestamp'],
+            },
+        ),
+    ]