diff --git a/lib/tasks/initializers.rake b/lib/tasks/initializers.rake
index 6da60c147..564fbff9f 100644
--- a/lib/tasks/initializers.rake
+++ b/lib/tasks/initializers.rake
@@ -5,6 +5,8 @@ file 'config/initializers/secret_token.rb' do
   secret = SecureRandom.hex(40)
   File.open(path, 'w') do |f|
     f.write <<"EOF"
+# frozen_string_literal: true
+
 # This file was generated by 'rake generate_secret_token', and should
 # not be made visible to public.
 # If you have a load-balancing Redmine cluster, you will need to use the