UPD: dav_events: decoupled event model and eventflag model.

dav_events/models/eventflag.py

@@ -0,0 +1,31 @@
+from django.conf import settings
+from django.db import models
+from django.utils import timezone
+
+from ..utils import get_ghost_user, get_system_user
+
+
+def get_system_user_id():
+    return get_system_user().id
+
+
+class EventFlag(models.Model):
+    event = models.ForeignKey('dav_events.Event', related_name='flags')
+    status = models.ForeignKey('dav_events.EventStatus',
+                               on_delete=models.PROTECT,
+                               related_name='+')
+    timestamp = models.DateTimeField(default=timezone.now)
+    user = models.ForeignKey(settings.AUTH_USER_MODEL,
+                             default=get_system_user_id,
+                             on_delete=models.SET(get_ghost_user),
+                             related_name='+')
+
+    class Meta:
+        ordering = ['event', 'timestamp', 'status']
+
+    def __unicode__(self):
+        s = u'{status} - {timestamp}'
+        if self.user:
+            s += u' by user {user}'
+        return s.format(status=self.status, timestamp=self.timestamp.strftime('%d.%m.%Y %H:%M:%S'),
+                        user=self.user)