Update README.md

Author: localden

README.md

@@ -16,6 +16,7 @@
 
 - [🤔 What is Spec-Driven Development?](#-what-is-spec-driven-development)
 - [⚡ Get started](#-get-started)
+- [📽️ Video Overview](#️-video-overview)
 - [🔧 Specify CLI Reference](#-specify-cli-reference)
 - [📚 Core philosophy](#-core-philosophy)
 - [🌟 Development phases](#-development-phases)