Freeze ModelName cache_key also

activesupport/lib/active_support/core_ext/module/model_naming.rb

@@ -6,7 +6,7 @@ def initialize(name)
       super
       @singular = underscore.tr('/', '_').freeze
       @plural = @singular.pluralize.freeze
-      @cache_key = tableize
+      @cache_key = tableize.freeze
       @partial_path = "#{@cache_key}/#{demodulize.underscore}".freeze
     end
   end