Update core_ext.rb
Update core_ext.rb

GH-317 is currently under discussion. In the meanwhile, make sure to not override Rails 3.x projects.
bandzoogle/whois,krautcomputing/whois,linrock/whois,ledowong/whois,songm5178/whois,weppos/whois,Shopify/whois,owenwarner/whois,otzy007/whois,Shopify/whois,mattbrictson/whois,kubihie/whois,ipmobiletech/whois