error out if an invalid RUBY_VERSION is specified
error out if an invalid RUBY_VERSION is specified

moneyadviceservice/heroku-buildpack-ruby-bowndler,erintherad/heroku-buildpack-ruby,jayshreeanand/heroku-buildpack-ruby,stolt45/heroku-buildpack-ruby-with-sqlite3,jumptvs/BP_Ruby,schu/buildpack-testing,redhotvengeance/heroku-buildpack-deep-thought,CPPWind/ruby-buildpack,pcincalifornia/wdc-heroku-buildpack-middleman,CPPWind/ruby-buildpack,12spokes/heroku-buildpack-ruby-imagemagick,awebneck/heroku-buildpack-canvas,orenyk/heroku-buildpack-ruby,progrium/heroku-buildpack-ruby,Micka33/heroku-buildpack-ruby-liblua,Genius/heroku-buildpack-ruby,barakav/heroku-buildpack-ruby,blueapron/heroku-buildpack-ruby,wolfoo2931/heroku-buildpack-ruby-2a352ae,packetmonkey/heroku-buildpack-ruby,davidjrice/heroku-buildpack-couchbase-ruby,WilliamDenniss/heroku-buildpack-ruby-imagemagick,ndbroadbent/heroku-buildpack-turbo-sprockets,joshco/heroku-buildpack-ruby,Jonty/ruby-buildpack,awebneck/heroku-buildpack-canvas,reesio/heroku-buildpack-ruby,jonseaberg/heroku-buildpack-turbo-sprockets,d-reinhold/cf-buildpack-ruby,firmhouse/heroku-buildpack-ruby-freetds,sky-uk/ruby-buildpack,sanemat/heroku-buildpack-ruby-tachikoma,sgnpa/heroku-buildpack-cas,zunda/heroku-buildpack-ruby,righi/instacart-heroku-buildpack,lemurheavy/heroku-buildpack-ruby,barakav/heroku-buildpack-ruby,centresource/heroku-buildpack-turbo-sprockets-pmp-ffm,hatofmonkeys/ruby-testing-buildpack,michaelphines/alexa-nest,orenyk/heroku-buildpack-ruby,hixi/heroku-buildpack-ruby,millie/heroku-buildpack-ruby-with-pdftk,jgable/buildpack-ruby-rack-setup-tasks,cloudn/buildpack-ruby,Altoros/ruby-buildpack,tenjikinc/heroku-buildpack-ruby,Scalingo/ruby-buildpack,dleavitt/heroku-buildpack-ruby,recursecenter/heroku-buildpack-ruby,donnykurnia/heroku-buildpack-ruby,iamjarvo/ruby-buildpack,adaptivelab/heroku-buildpack-adaptivelab-website-2,jgarber/heroku-buildpack-ruby-octopress,teodor-pripoae/heroku-buildpack-ruby,ablease/custom-buildpack,d-reinhold/cf-buildpack-ruby,jasonlevens/heroku-buildpack-ruby,cordata/heroku-buildpack-ruby,dleavitt/heroku-buildpack-ruby,pkgr/heroku-buildpack-ruby,HYPERHYPER/heroku-buildpack-ruby,cloudfoundry/ruby-buildpack,brightbytes/heroku-buildpack-ruby-without-assets-precompile,aarongray/heroku-buildpack-ruby,takii/heroku-buildpack-ruby,takii/db2rubybuildpack,tomwolfe/heroku-buildpack-gsl-ruby,davidjrice/heroku-buildpack-couchbase-ruby,ChefSteps/heroku-buildpack-ruby,jcamenisch/heroku-buildpack-rgeo,Scalingo/ruby-buildpack,vhx/heroku-buildpack,takii/db2rubybuildpack,cloudfoundry/ruby-buildpack,fgbreel/heroku-buildpack-ruby,ericroberts/heroku-buildpack-ruby,gbenedict/heroku-buildpack-ruby,gls1/heroku-buildpack-ruby-pdftk,cloudfoundry/ruby-buildpack,gls1/heroku-buildpack-ruby-pdftk,Dim25/heroku-buildpack-ruby-GSL,ActiveState/heroku-buildpack-ruby,hellojustin/heroku-buildpack-custom-ruby,mrhenry/heroku-buildpack-ruby,0x00evil/heroku-buildpack-ruby,qnyp/heroku-buildpack-ruby-bower,crdschurch/heroku-buildpack-ruby,phusion/heroku-buildpack-ruby,pcincalifornia/wdc-heroku-buildpack-middleman,tenjikinc/heroku-buildpack-ruby,qstream/heroku-buildpack-ruby,centresource/heroku-buildpack-turbo-sprockets-pmp-ffm,shuber/heroku-buildpack-ruby,ejholmes/heroku-buildpack-middleman,centresource/heroku-buildpack-turbo-sprockets-pmp-ffm,ekaranto/rails4-bluemix-buildpack,daltonrenaldo/heroku-buildpack-ruby,cloudn/buildpack-ruby,hpcloud/ruby-buildpack,teodor-pripoae/heroku-buildpack-ruby,ltrademark/heroku-buildpack-ruby,iamjarvo/ruby-buildpack,nthj/heroku-buildpack-mirror,daltonrenaldo/heroku-buildpack-ruby,mattwalters/heroku-buildpack-ruby,bskyb-commerce/ruby-buildpack,gls1/heroku-buildpack-ruby-pdftk-new,jonasoberschweiber/heroku-buildpack-ruby,bwaite-jaroop/heroku-buildpack-ruby,instacart/heroku-buildpack-ruby,hpcloud/heroku-buildpack-ruby,leonardykris/mos-ruby-buildpack,samfrench/heroku-buildpack-ruby,bskyb-commerce/help-heroku-buildpack,engineyard/heroku-buildpack-ruby,fcruxen/ruby-buildpack,wycats/heroku-buildpack-middleman,takii/db2rubybuildpack,recursecenter/heroku-buildpack-ruby,markaschneider/heroku-buildpack-ruby-ffmpeg-sox,bskyb-commerce/ruby-buildpack,Altoros/ruby-buildpack,ascot21/heroku-buildpack-turbo-sprockets,samfrench/heroku-buildpack-ruby,jumptvs/BP_Ruby,jonasoberschweiber/heroku-buildpack-ruby,KoanHealth/heroku-buildpack-marvin-setup,takii/heroku-buildpack-ruby,sky-uk/ruby-buildpack,trumaker/heroku-buildpack-turbo-sprockets,zidekmat/buildpack-ruby,amaltson/heroku-buildpack-ruby,AdStage/heroku-buildpack-ruby,phusion/heroku-buildpack-ruby,Altoros/ruby-buildpack,pietrop/heroku-buildpack-ruby,meskyanichi/heroku-buildpack-middleman,tdenovan/heroku-buildpack-ruby,HYPERHYPER/heroku-buildpack-ruby,codykrieger/heroku-buildpack-jekyll,Nedomas/heroku-buildpack-ruby-minus-node-with-node-paths,0x00evil/heroku-buildpack-ruby,electricobjects/heroku-buildpack-ruby,scottatron/moc-buildpack,hausdorff/heroku-buildpack-ruby-jekyll,pkgr/buildpack-ruby-precise-old,atmos/heroku-buildpack-ruby,mattwalters/heroku-buildpack-ruby,electricobjects/heroku-buildpack-ruby,andycroll/heroku-buildpack-jekyll,leonardykris/mos-ruby-buildpack,vhx/heroku-buildpack,firmhouse/heroku-buildpack-ruby-freetds,sgnpa/heroku-buildpack-cas,thirdprestige/heroku-buildpack-ruby,dieze/heroku-buildpack-ruby-hooks,diasks2/heroku-buildpack-mecab,derrek/heroku-buildpack-ruby,qstream/heroku-buildpack-ruby,aarongray/heroku-buildpack-ruby,mintybit/heroku-buildpack-ruby,Altoros/ruby-buildpack,cmaggard/heroku-buildpack-turbo-sprockets,stefansundin/heroku-buildpack-ruby,shuber/heroku-buildpack-ruby,dtao/deft-buildpack-ruby,Dim25/heroku-buildpack-ruby-GSL,dlorson/gentle-buildpack,sstelfox/buildpack-ruby,ilpoldo/heroku-buildpack-ruby,tpope/heroku-buildpack-ruby-tpope,trumaker/heroku-buildpack-turbo-sprockets,ekaranto/rails4-bluemix-buildpack,pkgr/heroku-buildpack-ruby,rowanoulton/heroku-buildpack-ruby,redhotvengeance/heroku-buildpack-deep-thought,bskyb-commerce/help-heroku-buildpack,nicholasmott/heroku-buildpack-octopress,thewebguy/heroku-buildpack-ruby-ffmpeg-libsndfile,ChefSteps/heroku-buildpack-ruby,jonseaberg/heroku-buildpack-turbo-sprockets,travis-ci/heroku-buildpack-ruby,erintherad/heroku-buildpack-ruby,zoomer/heroku-buildpack-ruby-bower,sgnpa/heroku-buildpack-cas,Git-Host/prelang-buildpack,bwaite-jaroop/heroku-buildpack-ruby,ericroberts/heroku-buildpack-ruby,qnyp/heroku-buildpack-ruby-bower,guidance-guarantee-programme/heroku-buildpack-princexml-old,sky-uk/ruby-buildpack,simonnordberg/heroku-buildpack-ruby,CPPWind/ruby-buildpack,sanemat/heroku-buildpack-ruby-tachikoma,space150/heroku-buildpack-ruby,bellycard/heroku-buildpack-ruby,hone/heroku-buildpack-ruby,lemurheavy/heroku-buildpack-ruby,pilotcreative/heroku-buildpack-ruby,dlorson/gentle-buildpack,swipesense/heroku-buildpack-ruby,hausdorff/heroku-buildpack-ruby-jekyll,nthj/heroku-buildpack-mirror,Micka33/heroku-buildpack-ruby-liblua,lyoshenka/heroku-buildpack-ruby-jekyll,phusion/heroku-buildpack-ruby,atmos/heroku-buildpack-ruby,jasonlevens/heroku-buildpack-ruby,icelab/heroku-buildpack-ruby,scottatron/moc-buildpack,orlando/heroku-buildpack-ruby,hellojustin/heroku-buildpack-custom-ruby,DyegoCosta/heroku-buildpack-ruby,catalyzeio/buildpack-ruby,brightbytes/heroku-buildpack-ruby-without-assets-precompile,adaptivelab/heroku-buildpack-adaptivelab-website-2,DigitalInnovation/heroku-buildpack-mslabs,jumptvs/BP_Ruby,jumptvs/BP_Ruby,tpope/heroku-buildpack-ruby-tpope,Jonty/ruby-buildpack,dtao/teeny-buildpack,Jonty/ruby-buildpack,ilpoldo/heroku-buildpack-ruby,jeremyvdw/heroku-buildpack-ruby-jekyll,CPPWind/ruby-buildpack,pavgup/heroku-buildpack-ruby-lateslugignore,ablease/custom-buildpack,hone/heroku-buildpack-ruby,nicholasmott/heroku-buildpack-octopress,pavgup/heroku-buildpack-ruby-lateslugignore,d-reinhold/cf-buildpack-ruby,jayshreeanand/heroku-buildpack-ruby,catalyzeio/buildpack-ruby,AdStage/heroku-buildpack-ruby,musicglue/heroku-buildpack-ruby,sky-uk/help-heroku-buildpack,cloudControl/buildpack-ruby,allomov/fat-free-heroku-buildpack-ruby,ericboehs/heroku-buildpack-ruby,ascot21/heroku-buildpack-turbo-sprockets,blueapron/heroku-buildpack-ruby,engineyard/heroku-buildpack-ruby,mintybit/heroku-buildpack-ruby,hatofmonkeys/ruby-testing-buildpack,Numerico/heroku-buildpack-ruby,mattmanning/heroku-buildpack-ruby-jekyll,cloudn/buildpack-ruby,12spokes/heroku-buildpack-ruby-imagemagick,derrek/heroku-buildpack-ruby,millie/heroku-buildpack-ruby-with-pdftk,pkgr/buildpack-ruby-precise-old,rhomobile/heroku-buildpack-ruby,joshco/heroku-buildpack-ruby,AJamesPhillips/heroku-buildpack-ruby,beydogan/ruby-buildpack,cmaggard/heroku-buildpack-turbo-sprockets,cloudfoundry/ruby-buildpack,WilliamDenniss/heroku-buildpack-ruby-imagemagick,stefansundin/heroku-buildpack-ruby,mperejda/heroku-buildpack-ruby,diasks2/heroku-buildpack-mecab,travis-ci/heroku-buildpack-ruby,sky-uk/help-heroku-buildpack,makifund/heroku-buildpack-ruby,zidekmat/buildpack-ruby,Git-Host/prelang-buildpack,ruby/heroku-buildpack-www-ruby-lang,guidance-guarantee-programme/heroku-buildpack-princexml-old,zunda/heroku-buildpack-ruby,pietrop/heroku-buildpack-ruby,wakermahmud/heroku-buildpack-jekyll,ablease/custom-buildpack,beydogan/ruby-buildpack,stolt45/heroku-buildpack-ruby-with-sqlite3,pkgr/buildpack-ruby-precise-old,rstacruz/heroku-buildpack-middleman,wakermahmud/heroku-buildpack-jekyll,ekaranto/rails4-bluemix-buildpack,fgbreel/heroku-buildpack-ruby,hpcloud/ruby-buildpack,fcruxen/ruby-buildpack,mrhenry/heroku-buildpack-ruby,mperejda/heroku-buildpack-ruby,musicglue/heroku-buildpack-ruby,donnykurnia/heroku-buildpack-ruby,ekaranto/rails4-bluemix-buildpack,Numerico/heroku-buildpack-ruby,codykrieger/heroku-buildpack-jekyll,gls1/heroku-buildpack-ruby-pdftk-new,takii/db2rubybuildpack,mattmanning/heroku-buildpack-ruby-jekyll,space150/heroku-buildpack-ruby,meskyanichi/heroku-buildpack-middleman,andycroll/heroku-buildpack-jekyll,amaltson/heroku-buildpack-ruby,AJamesPhillips/heroku-buildpack-ruby,bellycard/heroku-buildpack-ruby,anay/buildpack-ruby-with-oracle-jdk,bskyb-commerce/ruby-buildpack,wolfoo2931/heroku-buildpack-ruby-2a352ae,hixi/heroku-buildpack-ruby,Jonty/ruby-buildpack,progrium/heroku-buildpack-ruby,tdenovan/heroku-buildpack-ruby,cordata/heroku-buildpack-ruby,rowanoulton/heroku-buildpack-ruby,anay/buildpack-ruby-with-oracle-jdk,hpcloud/ruby-buildpack,michaelphines/alexa-nest,WilliamDenniss/heroku-buildpack-ruby-imagemagick,dtao/deft-buildpack-ruby,ejholmes/heroku-buildpack-middleman,schu/heroku-buildpack-ruby,dtao/teeny-buildpack,pilotcreative/heroku-buildpack-ruby,reesio/heroku-buildpack-ruby,jgarber/heroku-buildpack-ruby-octopress,heroku/heroku-buildpack-ruby,AdStage/heroku-buildpack-ruby,ibmdb/db2rubybuildpack,ibmdb/db2rubybuildpack,sanemat/heroku-buildpack-ruby-tachikoma,tomwolfe/heroku-buildpack-gsl-ruby,firmhouse/heroku-buildpack-ruby-freetds,Genius/heroku-buildpack-ruby,progrium/heroku-buildpack-ruby,icelab/heroku-buildpack-ruby,DigitalInnovation/heroku-buildpack-mslabs,iamjarvo/ruby-buildpack,ibmdb/db2rubybuildpack,rstacruz/heroku-buildpack-middleman,jgarber/heroku-buildpack-ruby-octopress,makifund/heroku-buildpack-ruby,travis-ci/heroku-buildpack-ruby,allomov/fat-free-heroku-buildpack-ruby,ActiveState/heroku-buildpack-ruby,zoomer/heroku-buildpack-ruby-bower,ltrademark/heroku-buildpack-ruby,jcamenisch/heroku-buildpack-rgeo,cloudControl/buildpack-ruby,iamjarvo/ruby-buildpack,fcruxen/ruby-buildpack,hpcloud/ruby-buildpack,jeremyvdw/heroku-buildpack-ruby-jekyll,DouglasAllen/heroku-buildpack-ruby,hpcloud/heroku-buildpack-ruby,davidjrice/heroku-buildpack-couchbase-ruby,thirdprestige/heroku-buildpack-ruby,righi/instacart-heroku-buildpack,gbenedict/heroku-buildpack-ruby,lyoshenka/heroku-buildpack-ruby-jekyll,jglascoe/heroku-buildpack-ruby-jekyll,jgable/buildpack-ruby-rack-setup-tasks,schu/buildpack-testing,DouglasAllen/heroku-buildpack-ruby,moneyadviceservice/heroku-buildpack-ruby-bowndler,nicholasmott/heroku-buildpack-octopress,hatofmonkeys/ruby-testing-buildpack,thirdprestige/heroku-buildpack-ruby,markaschneider/heroku-buildpack-ruby-ffmpeg-sox,ndbroadbent/heroku-buildpack-turbo-sprockets,Numerico/heroku-buildpack-ruby,cloudn/buildpack-ruby,bskyb-commerce/ruby-buildpack,swipesense/heroku-buildpack-ruby,rvizza/heroku-buildpack-gsl-ruby,wycats/heroku-buildpack-middleman,darron/heroku-buildpack-ruby-jekyll,dieze/heroku-buildpack-ruby-hooks,atmos/heroku-buildpack-ruby,packetmonkey/heroku-buildpack-ruby,DyegoCosta/heroku-buildpack-ruby,darron/heroku-buildpack-ruby-jekyll,ablease/custom-buildpack,thewebguy/heroku-buildpack-ruby-ffmpeg-libsndfile,sstelfox/buildpack-ruby,crdschurch/heroku-buildpack-ruby,jglascoe/heroku-buildpack-ruby-jekyll,lemurheavy/heroku-buildpack-ruby,simonnordberg/heroku-buildpack-ruby,KoanHealth/heroku-buildpack-marvin-setup,rvizza/heroku-buildpack-gsl-ruby,orlando/heroku-buildpack-ruby,ericboehs/heroku-buildpack-ruby,AJamesPhillips/heroku-buildpack-ruby,Nedomas/heroku-buildpack-ruby-minus-node-with-node-paths,fcruxen/ruby-buildpack,sky-uk/ruby-buildpack,schu/heroku-buildpack-ruby,cloudfoundry/ruby-buildpack,pavgup/heroku-buildpack-ruby-lateslugignore,instacart/heroku-buildpack-ruby,rhomobile/heroku-buildpack-ruby,heroku/heroku-buildpack-ruby