rails new --builder

When invoking rails new with the --builder option, I see that you have to call the class ::AppBuilder. How can you

change the source_root for just a few of the methods?

I want to generate the gemfile from my own template

AppBuilder < Rails::AppBuilder

def gemfile

template 'Gemfile'

end

end

How can I change the Gemfile template from the AppBuilder and if I can't what is the use of the --builder option?

thanks,

Dominic