diff --git a/app/controllers/application_controller.rb b/app/controllers/application_controller.rb
index 1f2a1c38..421313aa 100644
--- a/app/controllers/application_controller.rb
+++ b/app/controllers/application_controller.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class ApplicationController < ActionController::Base
   BROWSER_LOCALE_REGEXP = /\A\w{2}(?:-\w{2})?/