Add license to gemspec, is MIT
Add license to gemspec, is MIT

Fixes #303
Fixes #304

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