Fix release script to allow pre release gems
Fix release script to allow pre release gems

This addition of `--pre` fixes the issue we were seeing when installing
a local copy of a pre-release rails version.

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