Chef course added in courses/free-courses-en.md (#8427)

* Chef course added in courses/free-courses-en.md

* Added this course(chef) under DevOps

courses/free-courses-en.md

@@ -29,6 +29,7 @@
 * [Deep Learning](#deep-learning)
 * [DevOps](#devops)
     * [Ansible](#ansible)
+    * [Chef](#chef)
 * [Digital Electronics](#digital-electronics)
 * [Docker](#docker)
 * [Elastic](#elastic)
@@ -489,6 +490,12 @@
 * [Use Ansible with Amazon Web Services](https://www.udemy.com/course/ansible-aws) - Rohit Abraham (Udemy)
 
 
+###Chef
+
+* [CHEF Tutorial](https://www.youtube.com/playlist?list=PLsgnv1SN76ILtD3TnVtXpX1hmwjyY9OuT) - Online Tutorials
+* [Learning Chef](https://www.youtube.com/playlist?list=PLKK5zTDXqzFM53J6-rikDrqbbY0Pu-9SP) - Nathen Harvey
+
+
 ### Digital Electronics
 
 * [Digital Electronics](https://www.youtube.com/playlist?list=PLBlnK6fEyqRjMH3mWf6kwqiTbT798eAOm) - Neso Academy