Add Ruby v2.4.0-rc1 to Travis matrix
Add Ruby v2.4.0-rc1 to Travis matrix

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