Add GNU Coreutils Package Guide

- Add GNU Coreutils Package Guide
- Add contributors badge

Signed-off-by: Joe Block <jpb@unixorn.net>

Author: unixorn

README.md

@@ -1,6 +1,7 @@
 # sysadmin-reading-list
 
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@@ -85,6 +86,7 @@ So you've got your first sysadmin/sre job or internship. Congratulations, it's g
 - [DevOps Roadmap](https://roadmap.sh/devops) - Community driven, articles, resources, guides, interview questions, quizzes for DevOps. Learn to become a modern DevOps engineer by following the steps, skills, resources and guides listed in this roadmap.
 - [Effective DevOps](http://shop.oreilly.com/product/0636920039846.do) - A practical guide for creating affinity among teams and promoting efficient tool usage in your company.
 - [Git Magic (free ebook)](http://www-cs-students.stanford.edu/~blynn/gitmagic/) - `git` is a version control Swiss army knife. A reliable versatile multipurpose revision control tool whose extraordinary flexibility makes it tricky to learn, let alone master.
+- [GNU Coreutils Package Guide](https://blog.robertelder.org/gnu-coreutils-package-guide/) - Robert Elder made a short YouTube video describing every command in the GNU Coreutils package. I guarantee you will discover something new.
 - [Hello DNS](https://github.com/ahupowerdns/hello-dns) - Every sysadmin/sre needs to know how DNS works. Start with [DNS Basics](https://github.com/ahupowerdns/hello-dns/blob/master/basic.md) it's a good introduction.
 - [Lean Startup](https://smile.amazon.com/Lean-Startup-Entrepreneurs-Continuous-Innovation/dp/0307887898) or [Lean Enterprise](https://smile.amazon.com/Lean-Enterprise-Performance-Organizations-Innovate/dp/1449368425) - This pair describes the process surrounding implementation and use of Lean principles in Startup and Enterprise organizations. There are a number of companion pieces that extend the principles to specific fields of study and implementation, such as [Lean Analytics](https://smile.amazon.com/Lean-Analytics-Better-Startup-Faster/dp/1449335675).
 - [Lessons Learned from Twenty Years of Site Reliability Engineering](https://sre.google/resources/practices-and-processes/twenty-years-of-sre-lessons-learned/) - Google blog post about lessons learned over their first 20 years running data centers.