How to insert header in generated files

Answer 1

I can't think of an automated way to do this, other than editing the generator code.

You could consider using a snippet for your editor of choice.

Answer 2

You could run a rake test to add the headers to all the files. Check out how it works on the Annotate gem (http://github.com/ctran/annotate_models). You'll likely have to run it on all your .rb files, but the main idea sustains.