flash upload should work with any session storage

app/middleware/flash_session_cookie_middleware.rb

@@ -13,7 +13,6 @@ class FlashSessionCookieMiddleware
                              req.params[@session_key] ].join('=').freeze unless req.params[@session_key].nil?
       env['HTTP_ACCEPT'] = "#{req.params['_http_accept']}".freeze unless req.params['_http_accept'].nil?
     end
-    
     @app.call(env)
   end
 end

config/initializers/session_store.rb

@@ -3,7 +3,7 @@
 Balder::Application.config.session_store :cookie_store, :key => '_balder_session'
 
 Rails.application.config.middleware.insert_before(
-  ActionDispatch::Session::CookieStore,
+  Rails.application.config.session_store,
   FlashSessionCookieMiddleware,
   Rails.application.config.session_options[:key]
 )