Updated AR-specific reference to use Polyamorous
Updated AR-specific reference to use Polyamorous

Changed reference from a version-dependent AR class to a better, more reliable Polyamorous one
AndrewSwerlick/ransack,outstand/ransack,reinteractive/ransack,Eric-Guo/ransack,johan--/ransack,avit/ransack,mariorcardoso/ransack,activerecord-hackery/ransack,martndemus/ransack,Mario245/ransack,roman-franko/ransack,guilleva/ransack,laserlemon/ransack