mongodb specs fixed for rails >= 4
mongodb specs fixed for rails >= 4

activerecord-hackery/ransack,Mario245/ransack,vaski/ransack,nagyt234/ransack,martndemus/ransack,mariorcardoso/ransack,avit/ransack,roman-franko/ransack,guilleva/ransack,amboxer21/ransack,Eric-Guo/ransack,outstand/ransack,AndrewSwerlick/ransack,laserlemon/ransack,johan--/ransack,reinteractive/ransack