Added Homebrew.install_gem!
Added Homebrew.install_gem!

Useful when gem does not install with executable

hanxue/linuxbrew,hanxue/linuxbrew,MikeMcQuaid/brew,JCount/brew,mgrimes/brew,DomT4/brew,DomT4/brew,reitermarkus/brew,JCount/brew,ilovezfs/brew,nandub/brew,claui/brew,reitermarkus/brew,Linuxbrew/brew,EricFromCanada/brew,mahori/brew,ilovezfs/brew,sjackman/homebrew,Linuxbrew/brew,Homebrew/brew,mgrimes/brew,vitorgalvao/brew,MikeMcQuaid/brew,sjackman/homebrew,nandub/brew,MikeMcQuaid/brew,EricFromCanada/brew,Homebrew/brew,claui/brew,ilovezfs/brew,sjackman/homebrew,Linuxbrew/brew,EricFromCanada/brew,nandub/brew,konqui/brew,Homebrew/brew,Homebrew/brew,mahori/brew,mahori/brew,MikeMcQuaid/brew,claui/brew,JCount/brew,Linuxbrew/brew,vitorgalvao/brew,nandub/brew,mahori/brew,maxim-belkin/brew,reitermarkus/brew,EricFromCanada/brew,reitermarkus/brew,konqui/brew,DomT4/brew,JCount/brew,vitorgalvao/brew,hanxue/linuxbrew,claui/brew,DomT4/brew,maxim-belkin/brew,konqui/brew,maxim-belkin/brew,mgrimes/brew,sjackman/homebrew,vitorgalvao/brew,konqui/brew