diff -r 4c3ae065f22c -r 3b3999550508 src/notes/models/base.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/notes/models/base.py	Thu Jun 08 17:57:57 2017 +0200
@@ -0,0 +1,27 @@
+"""
+base abstract models
+"""
+import uuid
+
+from concurrency.fields import AutoIncVersionField
+from django.db import models
+from django.utils.translation import ugettext_lazy as _
+
+
+class ModelManager(models.Manager):
+    def get_by_natural_key(self, ext_id):
+        return self.get(ext_id=ext_id)
+
+class Model(models.Model):
+    objects = ModelManager()
+
+    created = models.DateTimeField(auto_now_add=True, verbose_name=_('Model|created'))
+    updated = models.DateTimeField(auto_now=True, verbose_name=_('Model|updated'))
+    ext_id = models.UUIDField(unique=True, default=uuid.uuid4, verbose_name=_('Model|ext_id'))
+    version = AutoIncVersionField(verbose_name=_('Model|version'))
+
+    def natural_key(self):
+        return (self.ext_id, )
+
+    class Meta:
+        abstract = True