Added Docker Crash Course Tutorial (#11243)

Co-authored-by: Godwin Odenigbo <godwintrav@gmail>

courses/free-courses-en.md

@@ -665,6 +665,7 @@
 * [Deploying Containerized Applications Technical Overview](https://www.udemy.com/course/deploying-containerized-applications-technical-overview) - Red Hat
 * [Docker](https://www.youtube.com/playlist?list=PLhW3qG5bs-L99pQsZ74f-LC-tOEsBp2rK) - Raghav Pal
 * [Docker and Kubernetes Complete Tutorial](https://www.youtube.com/playlist?list=PL0hSJrxggIQoKLETBSmgbbvE4FO_eEgoB) - Analytics Excellence
+* [Docker Crash Course Tutorial](https://www.youtube.com/playlist?list=PL4cUxeGkcC9hxjeEtdHFNYMtCpjNBm3h7) - Net Ninja
 * [Docker Essentials](https://cognitiveclass.ai/courses/docker-essentials) - CognitiveClass.ai
 * [Docker Tutorial for Beginners](https://www.youtube.com/watch?v=pTFZFxd4hOI) - Programming with Mosh!
 * [Docker Tutorial for Beginners](https://www.youtube.com/playlist?list=PL6gx4Cwl9DGBkvpSIgwchk0glHLz7CQ-7) - Thenewboston