Add reference to Concept Exercise Anatomy video (exercism#1227)

[Docs] Add reference to Concept Exercise Anatomy video

Author: ErikSchierboom

reference/implementing-a-concept-exercise.md

@@ -8,6 +8,10 @@ This document describes the steps required to implement a concept exercise for t
 - [Rationale for v3][docs-rationale-for-v3].
 - [What are concept exercise and how they are structured?][docs-concept-exercises]
 
+Please also watch the following video:
+
+- [The Anatomy of a Concept Exercise][anatomy-of-a-concept-exercise].
+
 As this document is generic, the following placeholders are used:
 
 - `<SLUG>`: the name of the exercise in kebab-case (e.g. `anonymous-methods`).
@@ -69,3 +73,4 @@ When implementing an exercise, it can be very useful to look at already implemen
 [docs-concept-exercises]: ../../../docs/concept-exercises.md
 [docs-rationale-for-v3]: ../../../docs/rationale-for-v3.md
 [docs-features-of-v3]: ../../../docs/features-of-v3.md
+[anatomy-of-a-concept-exercise]: https://www.youtube.com/watch?v=gkbBqd7hPrA