Housekeeping

[bryonye]

What does this PR do?

Add Resource(s) | Remove Resource(s) | Add info | Improve Repo

For resources

Description

Corrected some minor issues with README, CONTRIBUTING, and English language book list. Added missing file which is referenced in the README.

Why is this valuable (or not)

Improves quality of repo.

How do we know it's really free?

N/A

For book lists, is it a book?

N/A

Checklist:

• [x] Not a duplicate
• [x] Included author(s) if appropriate
• [x] Lists are in alphabetical order
• [x] Needed indications added (PDF, access notes, under construction)

[eshellman]

Thanks, and welcome to free-science-books!