class Rails::Generators::AppBase

def target_rails_prerelease(self_command = "new")
  return unless rails_prerelease? && bundle_install?
  if !File.exist?(File.expand_path("Gemfile", destination_root))
    create_file("Gemfile", <<~GEMFILE)
      source "https://rubygems.org"
      git_source(:github) { |repo| "https://github.com/\#{repo}.git" }
      #{rails_gemfile_entry}
    GEMFILE
    run_bundle
    @argv[0] = destination_root
    require "shellwords"
    bundle_command("exec rails #{self_command} #{Shellwords.join(@argv)}")
    exit
  else
    remove_file("Gemfile")
    remove_file("Gemfile.lock")
  end
end