Clean up the parent resource code.

[inferiorhumanorgans]

• String#scan will only return an empty array if string is empty
• Use File#split not String#scan + regexps + negative array indexes because the former's intent is more self-evident

[chrisroberts]

This is a very concise piece of cleanup. Thank you as this makes the code much clearer. The only issue is that the parent_path used to create the new resource will not be the same for the public vs. internal path. Thanks.