I don't think we should ship this as a default things for folks.

For better or worse, some folks really dislike Bundler (or name any gem really) and we're going to get the inevitable "why are you forcing this on me?"

I'd much rather just document this really well in the README as the way to handle this sort of thing.

This then gives us the option to if we want, provide modules for gem management: puppet-bundler, etc.