Fix rbx generated Gemfile regex
Fix rbx generated Gemfile regex

https://travis-ci.org/rails/rails/jobs/39190983#L460

 1) Failure:
 AppGeneratorTest#test_psych_gem
 [test/generators/app_generator_test.rb:495]:
 Expected /gem 'psych',\s+'~> 2.0', \s+platforms: :rbx/ to match <snip>
 http://git.io/uuLVag)\ngem 'psych', '~> 2.0', platforms: :rbx\n\n

esparta/rails,EmmaB/rails-1,hanystudy/rails,georgeclaghorn/rails,riseshia/railsguides.kr,maicher/rails,prathamesh-sonpatki/rails,lcreid/rails,shioyama/rails,sergey-alekseev/rails,Vasfed/rails,sealocal/rails,utilum/rails,arunagw/rails,kamipo/rails,MichaelSp/rails,repinel/rails,illacceptanything/illacceptanything,flanger001/rails,notapatch/rails,samphilipd/rails,kenta-s/rails,pvalena/rails,tijwelch/rails,travisofthenorth/rails,Sen-Zhang/rails,tjschuck/rails,BlakeWilliams/rails,printercu/rails,arunagw/rails,mathieujobin/reduced-rails-for-travis,untidy-hair/rails,gfvcastro/rails,riseshia/railsguides.kr,bogdanvlviv/rails,illacceptanything/illacceptanything,Stellenticket/rails,stefanmb/rails,kachick/rails,rafaelfranca/omg-rails,mtsmfm/rails,Envek/rails,ledestin/rails,shioyama/rails,yasslab/railsguides.jp,tijwelch/rails,deraru/rails,flanger001/rails,illacceptanything/illacceptanything,eileencodes/rails,esparta/rails,Erol/rails,elfassy/rails,joonyou/rails,elfassy/rails,baerjam/rails,koic/rails,kmayer/rails,aditya-kapoor/rails,coreyward/rails,kamipo/rails,iainbeeston/rails,ngpestelos/rails,rails/rails,starknx/rails,tjschuck/rails,Erol/rails,mohitnatoo/rails,bolek/rails,rbhitchcock/rails,odedniv/rails,coreyward/rails,bogdanvlviv/rails,kddeisz/rails,matrinox/rails,aditya-kapoor/rails,joonyou/rails,88rabbit/newRails,illacceptanything/illacceptanything,arjes/rails,rafaelfranca/omg-rails,travisofthenorth/rails,illacceptanything/illacceptanything,baerjam/rails,kenta-s/rails,esparta/rails,BlakeWilliams/rails,flanger001/rails,eileencodes/rails,prathamesh-sonpatki/rails,utilum/rails,Edouard-chin/rails,arjes/rails,jeremy/rails,alecspopa/rails,lcreid/rails,kddeisz/rails,Envek/rails,richseviora/rails,yawboakye/rails,yasslab/railsguides.jp,brchristian/rails,yalab/rails,yawboakye/rails,bradleypriest/rails,riseshia/railsguides.kr,palkan/rails,odedniv/rails,sergey-alekseev/rails,illacceptanything/illacceptanything,pvalena/rails,MSP-Greg/rails,gauravtiwari/rails,illacceptanything/illacceptanything,ngpestelos/rails,sealocal/rails,brchristian/rails,MSP-Greg/rails,Stellenticket/rails,arjes/rails,schuetzm/rails,joonyou/rails,MSP-Greg/rails,yhirano55/rails,Envek/rails,yhirano55/rails,richseviora/rails,felipecvo/rails,iainbeeston/rails,rossta/rails,mathieujobin/reduced-rails-for-travis,EmmaB/rails-1,voray/rails,tgxworld/rails,betesh/rails,gfvcastro/rails,printercu/rails,schuetzm/rails,mohitnatoo/rails,rails/rails,notapatch/rails,gavingmiller/rails,yasslab/railsguides.jp,yasslab/railsguides.jp,bogdanvlviv/rails,vassilevsky/rails,pschambacher/rails,amoody2108/TechForJustice,gavingmiller/rails,illacceptanything/illacceptanything,gfvcastro/rails,mtsmfm/rails,rbhitchcock/rails,kamipo/rails,voray/rails,yahonda/rails,xlymian/rails,aditya-kapoor/rails,stefanmb/rails,ledestin/rails,tjschuck/rails,rossta/rails,kirs/rails-1,vipulnsward/rails,vipulnsward/rails,bolek/rails,kirs/rails-1,illacceptanything/illacceptanything,amoody2108/TechForJustice,EmmaB/rails-1,kmcphillips/rails,ttanimichi/rails,sergey-alekseev/rails,yalab/rails,repinel/rails,mtsmfm/railstest,felipecvo/rails,pvalena/rails,rails/rails,kachick/rails,kaspth/rails,georgeclaghorn/rails,gcourtemanche/rails,deraru/rails,Spin42/rails,kachick/rails,Spin42/rails,betesh/rails,mtsmfm/railstest,kddeisz/rails,yahonda/rails,mohitnatoo/rails,gavingmiller/rails,starknx/rails,vassilevsky/rails,Vasfed/rails,MSP-Greg/rails,jeremy/rails,Erol/rails,koic/rails,kmayer/rails,starknx/rails,mechanicles/rails,eileencodes/rails,88rabbit/newRails,riseshia/railsguides.kr,palkan/rails,palkan/rails,vassilevsky/rails,untidy-hair/rails,joonyou/rails,stefanmb/rails,kmcphillips/rails,kddeisz/rails,kmcphillips/rails,yawboakye/rails,xlymian/rails,pvalena/rails,matrinox/rails,georgeclaghorn/rails,bradleypriest/rails,vipulnsward/rails,utilum/rails,notapatch/rails,hanystudy/rails,georgeclaghorn/rails,mechanicles/rails,ngpestelos/rails,rails/rails,mijoharas/rails,yalab/rails,Stellenticket/rails,rbhitchcock/rails,illacceptanything/illacceptanything,tgxworld/rails,assain/rails,kenta-s/rails,kirs/rails-1,palkan/rails,Edouard-chin/rails,yahonda/rails,arunagw/rails,bolek/rails,alecspopa/rails,assain/rails,travisofthenorth/rails,mohitnatoo/rails,schuetzm/rails,kmcphillips/rails,MichaelSp/rails,eileencodes/rails,fabianoleittes/rails,mijoharas/rails,repinel/rails,jeremy/rails,ledestin/rails,fabianoleittes/rails,pschambacher/rails,illacceptanything/illacceptanything,koic/rails,tijwelch/rails,illacceptanything/illacceptanything,pschambacher/rails,schuetzm/rails,odedniv/rails,rafaelfranca/omg-rails,repinel/rails,flanger001/rails,arunagw/rails,alecspopa/rails,mechanicles/rails,baerjam/rails,brchristian/rails,vipulnsward/rails,illacceptanything/illacceptanything,esparta/rails,BlakeWilliams/rails,marklocklear/rails,coreyward/rails,tgxworld/rails,amoody2108/TechForJustice,samphilipd/rails,kmayer/rails,Spin42/rails,matrinox/rails,kaspth/rails,assain/rails,mathieujobin/reduced-rails-for-travis,lucasmazza/rails,Vasfed/rails,lcreid/rails,ttanimic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