Added a model for logging actions

src/pretix/base/models/log.py

@@ -0,0 +1,30 @@
+from django.contrib.contenttypes.fields import GenericForeignKey
+from django.contrib.contenttypes.models import ContentType
+from django.db import models
+
+
+class LogEntry(models.Model):
+    """
+    Represents a change or action that has been performed on another object
+    in the database. This uses django.contrib.contenttypes to allow a
+    relation to an arbitrary database object.
+
+    :param user: The user that performed the action
+    :type user: User
+    :param action_type: The type of action that has been performed. This is
+       used to look up the renderer used to describe the action in a human-
+       readable way. This should be some namespaced value using dotted
+       notationto avaoid duplicates, e.g.
+       ``"pretix.plugins.banktransfer.incoming_transfer"``.
+    :type action_type: str
+    :param data: Arbitrary data that can be used by the log action renderer
+    :type data: str
+    """
+    content_type = models.ForeignKey(ContentType, on_delete=models.CASCADE)
+    object_id = models.PositiveIntegerField()
+    content_object = GenericForeignKey('content_type', 'object_id')
+    datetime = models.DateTimeField(auto_now_add=True)
+    user = models.ForeignKey('User', null=True, blank=True, on_delete=models.PROTECT)
+    event = models.ForeignKey('Event', null=True, blank=True, on_delete=models.CASCADE)
+    action_type = models.CharField(max_length=255)
+    data = models.TextField(default='{}')