diff --git a/config/mongoid.example.yml b/config/mongoid.example.yml
index 67496d6..f85c755 100644
--- a/config/mongoid.example.yml
+++ b/config/mongoid.example.yml
@@ -9,6 +9,7 @@
 
 defaults: &defaults
   host: localhost
+  identity_map_enabled: true
   # slaves:
   #   - host: slave1.local
   #     port: 27018
diff --git a/config/mongoid.mongohq.yml b/config/mongoid.mongohq.yml
index 381ff40..c3a38cb 100644
--- a/config/mongoid.mongohq.yml
+++ b/config/mongoid.mongohq.yml
@@ -5,4 +5,5 @@
 # commit it to your repo, then push to heroku.
 
 production:
-  uri: <%= ENV['MONGOHQ_URL'] %>
\ No newline at end of file
+  uri: <%= ENV['MONGOHQ_URL'] %>
+  identity_map_enabled: true
--
libgit2 0.21.2