def duration=(value)
      new_duration = value.to_s.split(":").reverse
      s, m = new_duration
      self[:duration] = (s.to_i + (m.to_i*60))
    end
def duration=(value)
      new_duration = value.to_s.split(":").reverse
      s, m = new_duration
      self[:duration] = (s.to_i + (m.to_i*60))
    end
Set the duration
 @param [String] duration as time