Check if ruby_version is not nil before running .match against 1.8.7
Check if ruby_version is not nil before running .match against 1.8.7

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