Add generic error log model.

Signed-off-by: Roberto Rosario <roberto.rosario.gonzalez@gmail.com>

mayan/apps/common/managers.py

@@ -0,0 +1,14 @@
+from __future__ import unicode_literals
+
+from django.apps import apps
+from django.contrib.contenttypes.fields import GenericRelation
+from django.conf import settings
+from django.db import models
+
+
+class ErrorLogEntryManager(models.Manager):
+    def register(self, model):
+        ErrorLogEntry = apps.get_model(
+            app_label='common', model_name='ErrorLogEntry'
+        )
+        model.add_to_class('error_logs', GenericRelation(ErrorLogEntry))