briannesbitt/Carbon — pull request #138 by jenssegers (2014-06-26 07:39:01+00:00)
Title: Make adding and substracting more flexible

This allows you to add and subtract intervals like:

Date::now()->sub('1 day');
Date::now()->add('1 day');

It basically automatically creates a DateInterval instance for you and passes it to the original add and sub methods.