diff --git a/README.md b/README.md
index dbb38e8..ca88a27 100644
--- a/README.md
+++ b/README.md
@@ -80,7 +80,7 @@ use Redis as the session store.
 MyApplication::Application.config.session_store :redis_store,
   servers: ["redis://localhost:6379/0/session"],
   expire_after: 90.minutes,
-  key: "_#{Rails.application.class.parent_name.downcase}_session",
+  key: "_#{Rails.application.class.module_parent_name.downcase}_session",
   threadsafe: true,
   secure: true
 ```