gistfile1.rb

class AuditLogger < Logger
  def format_message(severity, timestamp, progname, msg)
    "#{timestamp.to_formatted_s(:db)} #{severity} #{msg}\n"
  end
end

[:action_controller, :active_record].each do |fw|
  fw.to_s.camelize.constantize.const_get("Base").send(:define_method, :audit_log) do
    @@audit_log ||= AuditLogger.new(File.open(File.join(RAILS_ROOT, 'log', "audit_#{RAILS_ENV}.log"), 'a'))
  end
end