read_rc_file

# File railties/lib/rails/generators/rails/app/app_generator.rb, line 685
        def read_rc_file(railsrc)
          extra_args = File.readlines(railsrc).flat_map.each { |line| line.split("#", 2).first.split }
          puts "Using #{extra_args.join(" ")} from #{railsrc}"
          extra_args
        end