rails4.0.0.beta1 -> rails4.0.0.rc1 migration guide ref: http://qiita.com/items/6e19c246d608abd9795b

file0.txt

diff --git a/config/initializers/session_store.rb b/config/initializers/session_store.rb
index e3f861f..b7cac75 100644
--- a/config/initializers/session_store.rb
+++ b/config/initializers/session_store.rb
@@ -1,3 +1,3 @@
 # Be sure to restart your server when you modify this file.

-HogeCo::Application.config.session_store :encrypted_cookie_store, key: '_hoge_co_session'
+HogeCo::Application.config.session_store :cookie_store, key: '_hoge_co_session'

file1.txt

gems/railties-4.0.0.rc1/lib/rails/application/configuration.rb:144:in `const_get': uninitialized constant ActionDispatch::Session::EncryptedCookieStore (NameError)