diff --git a/app/helpers/view_helper.rb b/app/helpers/view_helper.rb
index 63f2aec5b9e..4bb09061d68 100644
--- a/app/helpers/view_helper.rb
+++ b/app/helpers/view_helper.rb
@@ -33,7 +33,7 @@ module ViewHelper
     30.minutes => N_("30 Minutes"),
     45.minutes => N_("45 Minutes"),
     1.hour     => N_("1 Hour")
-  }
+  }.freeze
 
   class << self
     def concat_tag(*args, &block)