Missing translators logger and visualizer for I18n

I18n.rb

I18n::Backend::Simple.include(I18n::Backend::Metadata)

# This will work with <%= t %> , not with <%= I18n.t %>
module ActionView
  module Helpers
    module TranslationHelper
      alias_method :translate_basic, :translate
      mattr_accessor :i18n_logger

      def translate(key, options = {})
        @i18n_logger ||= Logger.new("#{Rails.root}/log/I18n.log")
        @i18n_logger.info "Translate key '#{key}' with options #{options.inspect}"
        options.merge!(:rescue_format => :html) unless options.key?(:rescue_format)
        options.merge!(:locale => I18n.locale)  unless options.key?(:locale)
        reqested_locale = options[:locale].to_sym
        s = translate_basic(key, options)
        if s.translation_metadata[:locale] != reqested_locale &&
           options[:rescue_format] == :html && Rails.env.development?

           @i18n_logger.error "* Translate missing for key '#{key}' with options #{options.inspect}"
           missing_key = I18n.normalize_keys(reqested_locale, key, options[:scope])
           @i18n_logger.error "* Add key #{missing_key.join(".")}\n"

          %(<span class="translation_fallback" title="translation fallback #{reqested_locale}->#{s.translation_metadata[:locale]} for '#{key}'">#{s}</span>).html_safe
        else
          s
        end
      end
      alias :t :translate

    end
  end
end