threadsafe!

# File railties/lib/rails/application/configuration.rb, line 91
      def threadsafe!
        message = "config.threadsafe! is deprecated. Rails applications "                    "behave by default as thread safe in production as long as config.cache_classes and "                    "config.eager_load are set to true"
        ActiveSupport::Deprecation.warn message
        @cache_classes = true
        @eager_load = true
        self
      end