from django.db import models


class RevisionModelMixin(models.Model):

    class Meta:
        abstract = True

    _has_revision_support = True

    revision = models.PositiveIntegerField(default=0,
        db_index=True, editable=False)

    def save(self, *args, **kwargs):
        self.revision += 1
        super(RevisionModelMixin, self).save(*args, **kwargs)

from django.db import models
from django.contrib.contenttypes import generic


class RevisionModelMixin(models.Model):

    class Meta:
        abstract = True

    _has_revision_support = True

    revision = models.PositiveIntegerField(default=0,
        db_index=True, editable=False)

    versions = generic.GenericRelation('reversion.Version')

    def save(self, *args, **kwargs):
        self.revision += 1
        super(RevisionModelMixin, self).save(*args, **kwargs)

--- 
+++ 
@@ -1,5 +1,4 @@
 from django.db import models
-from django.contrib.contenttypes import generic
 
 
 class RevisionModelMixin(models.Model):
@@ -12,8 +11,6 @@
     revision = models.PositiveIntegerField(default=0,
         db_index=True, editable=False)
 
-    versions = generic.GenericRelation('reversion.Version')
-
     def save(self, *args, **kwargs):
         self.revision += 1
         super(RevisionModelMixin, self).save(*args, **kwargs)
Remove generic relation to reversion.Version from RevisionModelMixin
