Ruby on Rails 时间加上N天

问题：在RoR中需要在某个时间上添加N天，或者N小时

解决方案：

自： http://stackoverflow.com/questions/4654457/how-to-add-10-days-to-current-time-in-rails

Time.now + 10.days或10.days.from_now

自：http://stackoverflow.com/questions/1356457/is-there-an-add-days-in-ruby-datetime

Date.today + n.seconds # you can use 1.secondDate.today + n.minutes # you can use 1.minuteDate.today + n.hours # you can use 1.hourDate.today + n.days # you can use 1.dayDate.today + n.weeks # you can use 1.weekDate.today + n.months # you can use 1.monthDate.today + n.years # you can use 1.year