to_s (ActiveSupport::TimeWithZone)

    # File lib/active_support/time_with_zone.rb, line 151
        def to_s(format = :default)
          return utc.to_s(format) if format == :db
          if formatter = ::Time::DATE_FORMATS[format]
            formatter.respond_to?(:call) ? formatter.call(self).to_s : strftime(formatter)
          else
            "#{time.strftime("%Y-%m-%d %H:%M:%S")} #{formatted_offset(false, 'UTC')}" # mimicking Ruby 1.9 Time#to_s format
          end
        end