Update README concerning #uniq to de-dup results.
Update README concerning #uniq to de-dup results.

Follow-up to #477.

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