gemfile entry method need to return an empty array rather than nil (#27318)
gemfile entry method need to return an empty array rather than nil (#27318)

This fixes the following error when executing rails new command.

```
(erb):9:in `block in template': undefined method `comment' for nil:NilClass (NoMethodError)
```

Follow up to #27288
ttanimichi/rails,utilum/rails,betesh/rails,starknx/rails,mathieujobin/reduced-rails-for-travis,illacceptanything/illacceptanything,matrinox/rails,shioyama/rails,Sen-Zhang/rails,alecspopa/rails,lcreid/rails,rafaelfranca/omg-rails,starknx/rails,BlakeWilliams/rails,ngpestelos/rails,deraru/rails,Erol/rails,elfassy/rails,coreyward/rails,mijoharas/rails,starknx/rails,Spin42/rails,palkan/rails,odedniv/rails,shioyama/rails,schuetzm/rails,illacceptanything/illacceptanything,rossta/rails,eileencodes/rails,Envek/rails,illacceptanything/illacceptanything,tgxworld/rails,kmcphillips/rails,EmmaB/rails-1,kenta-s/rails,kddeisz/rails,yawboakye/rails,coreyward/rails,vipulnsward/rails,aditya-kapoor/rails,yalab/rails,Vasfed/rails,illacceptanything/illacceptanything,MSP-Greg/rails,riseshia/railsguides.kr,ttanimichi/rails,bradleypriest/rails,notapatch/rails,koic/rails,sealocal/rails,koic/rails,assain/rails,illacceptanything/illacceptanything,kddeisz/rails,hanystudy/rails,prathamesh-sonpatki/rails,Spin42/rails,yahonda/rails,georgeclaghorn/rails,lcreid/rails,shioyama/rails,sealocal/rails,xlymian/rails,koic/rails,BlakeWilliams/rails,hanystudy/rails,Stellenticket/rails,pvalena/rails,pschambacher/rails,jeremy/rails,arunagw/rails,kmayer/rails,kamipo/rails,rbhitchcock/rails,aditya-kapoor/rails,bolek/rails,bogdanvlviv/rails,tijwelch/rails,Sen-Zhang/rails,Spin42/rails,kirs/rails-1,eileencodes/rails,prathamesh-sonpatki/rails,voray/rails,Envek/rails,gavingmiller/rails,mohitnatoo/rails,MSP-Greg/rails,BlakeWilliams/rails,lcreid/rails,Stellenticket/rails,illacceptanything/illacceptanything,marklocklear/rails,kddeisz/rails,fabianoleittes/rails,repinel/rails,palkan/rails,maicher/rails,kddeisz/rails,samphilipd/rails,gavingmiller/rails,gfvcastro/rails,lucasmazza/rails,pvalena/rails,Edouard-chin/rails,yalab/rails,yawboakye/rails,Edouard-chin/rails,alecspopa/rails,riseshia/railsguides.kr,palkan/rails,yahonda/rails,arunagw/rails,felipecvo/rails,yahonda/rails,betesh/rails,yalab/rails,joonyou/rails,untidy-hair/rails,lucasmazza/rails,Erol/rails,betesh/rails,notapatch/rails,notapatch/rails,rails/rails,kaspth/rails,felipecvo/rails,printercu/rails,fabianoleittes/rails,iainbeeston/rails,illacceptanything/illacceptanything,Vasfed/rails,schuetzm/rails,kenta-s/rails,brchristian/rails,gauravtiwari/rails,xlymian/rails,shioyama/rails,eileencodes/rails,jeremy/rails,yhirano55/rails,flanger001/rails,flanger001/rails,bolek/rails,esparta/rails,yasslab/railsguides.jp,pvalena/rails,ledestin/rails,rbhitchcock/rails,tjschuck/rails,illacceptanything/illacceptanything,kirs/rails-1,yalab/rails,untidy-hair/rails,rafaelfranca/omg-rails,EmmaB/rails-1,EmmaB/rails-1,deraru/rails,bogdanvlviv/rails,mtsmfm/rails,tgxworld/rails,fabianoleittes/rails,lucasmazza/rails,bolek/rails,eileencodes/rails,flanger001/rails,richseviora/rails,felipecvo/rails,esparta/rails,pschambacher/rails,mohitnatoo/rails,illacceptanything/illacceptanything,printercu/rails,utilum/rails,sealocal/rails,travisofthenorth/rails,hanystudy/rails,gcourtemanche/rails,BlakeWilliams/rails,mechanicles/rails,kaspth/rails,rails/rails,tjschuck/rails,gavingmiller/rails,assain/rails,yasslab/railsguides.jp,gcourtemanche/rails,illacceptanything/illacceptanything,ledestin/rails,esparta/rails,riseshia/railsguides.kr,repinel/rails,marklocklear/rails,rbhitchcock/rails,aditya-kapoor/rails,brchristian/rails,yhirano55/rails,kirs/rails-1,repinel/rails,matrinox/rails,schuetzm/rails,rails/rails,matrinox/rails,esparta/rails,Edouard-chin/rails,travisofthenorth/rails,mohitnatoo/rails,mathieujobin/reduced-rails-for-travis,palkan/rails,ngpestelos/rails,Erol/rails,mechanicles/rails,utilum/rails,vipulnsward/rails,rossta/rails,coreyward/rails,jeremy/rails,printercu/rails,ngpestelos/rails,samphilipd/rails,kenta-s/rails,repinel/rails,georgeclaghorn/rails,samphilipd/rails,Envek/rails,illacceptanything/illacceptanything,gfvcastro/rails,Vasfed/rails,mtsmfm/railstest,baerjam/rails,mtsmfm/rails,Stellenticket/rails,rossta/rails,mtsmfm/railstest,yahonda/rails,iainbeeston/rails,alecspopa/rails,mechanicles/rails,illacceptanything/illacceptanything,illacceptanything/illacceptanything,rafaelfranca/omg-rails,printercu/rails,richseviora/rails,richseviora/rails,gauravtiwari/rails,jeremy/rails,prathamesh-sonpatki/rails,yhirano55/rails,maicher/rails,Envek/rails,schuetzm/rails,mijoharas/rails,marklocklear/rails,Erol/rails,mijoharas/rails,kmcphillips/rails,bradleypriest/rails,arunagw/rails,georgeclaghorn/rails,pschambacher/rails,bradleypriest/rails,mechanicles/rails,betesh/rails,gcourtemanche/rails,kmcphillips/rails,yawboakye/rails,baerjam/rails,assain/rails,riseshia/railsguides.kr,baerjam/rails,MSP-Greg/rails,ledestin/rails,travisofthenorth/rails,illacceptanything/illacceptanything,flanger001/rails,vipulnsward/rails,joonyou/rails,bogdanvlviv/rails,iainbeeston/rails,tijwelch/rails,gfvcastro/rails,mtsmfm/railstest,untidy-hair/rails,assain/rails,Sen-Zhang/rails,mtsmfm/rails,kamipo/rails,joonyou/rails,rails/rails,yhirano55/rails,lcreid/rails,mohitnatoo/rails,bogdanvlviv/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