def on(date, time_zone=Tod::TimeOfDay.time_zone)
      time_zone.local date.year, date.month, date.day, @hour, @minute, @second
    end
def on(date, time_zone=Tod::TimeOfDay.time_zone)
      time_zone.local date.year, date.month, date.day, @hour, @minute, @second
    end
Returns a Time instance on date using self as the time of day
 Optional time_zone will build time in that zone