Update CONTRIBUTING.md
Update CONTRIBUTING.md
jumptvs/BP_Ruby,cloudfoundry/ruby-buildpack,cloudfoundry/ruby-buildpack,jumptvs/BP_Ruby,jumptvs/BP_Ruby,cloudfoundry/ruby-buildpack,cloudfoundry/ruby-buildpack,ekaranto/rails4-bluemix-buildpack,ekaranto/rails4-bluemix-buildpack,cloudfoundry/ruby-buildpack,ekaranto/rails4-bluemix-buildpack,ekaranto/rails4-bluemix-buildpack,jumptvs/BP_Ruby