def to_s(format = :default)
      if format == :db
        utc.to_s(format)
      elsif 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 Time#to_s format
      end
    end
def to_s(format = :default)
      if format == :db
        utc.to_s(format)
      elsif 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 Time#to_s format
      end
    end
Returns a string of the object's date and time.
 Accepts an optional <tt>format</tt>:
 * <tt>:default</tt> - default value, mimics Ruby Time#to_s format.
 * <tt>:db</tt> - format outputs time in UTC :db time. See Time#to_formatted_s(:db).
 * Any key in <tt>Time::DATE_FORMATS</tt> can be used. See active_support/core_ext/time/conversions.rb.