def add(direction, count, distance)
      count = direction.downcase == 'b' ? -count.to_i : count.to_i

      case distance
      when 'd'
        @now + count
      when 'w'
        @now + count * 7
      when 'm'
        @now >> count
      when 'y'
        @now >> count * 12
      end

    end
def add(direction, count, distance)
      count = direction.downcase == 'b' ? -count.to_i : count.to_i

      case distance
      when 'd'
        @now + count
      when 'w'
        @now + count * 7
      when 'm'
        @now >> count
      when 'y'
        @now >> count * 12
      end

    end
Determines whether to move back or forward in time and returns the
 distance in days, weeks, months or years
 Example: move(10, 'd') adds 10 days to :now