class Chronic::RepeaterYear

def offset(span, amount, pointer)
  direction = pointer == :future ? 1 : -1
  sb = span.begin
  new_begin = Time.construct(sb.year + (amount * direction), sb.month, sb.day, sb.hour, sb.min, sb.sec)
  se = span.end
  new_end = Time.construct(se.year + (amount * direction), se.month, se.day, se.hour, se.min, se.sec)
  Chronic::Span.new(new_begin, new_end)
end