diff --git a/app/controllers/invitations_controller.rb b/app/controllers/invitations_controller.rb
index 8a85d09..d280a7e 100644
--- a/app/controllers/invitations_controller.rb
+++ b/app/controllers/invitations_controller.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # Copyright (C) 2024-2025 LibreWeddingPlanner contributors
 
 class InvitationsController < ApplicationController