TOC inside the docs

docs/BUILD_DEPLOY.md

@@ -1,5 +1,22 @@
 # Android Cast build ecosystem
 
+---
+
+## Table of contents
+
+<!-- toc -->
+- [Shared authentication](#shared-authentication)
+- [Local stack](#local-stack)
+- [Trigger a build](#trigger-a-build)
+- [Docker CI](#docker-ci)
+- [CircleCI](#circleci)
+- [Production notes](#production-notes)
+<!-- /toc -->
+
+**Documentation index:** [README.md](README.md)
+
+---
+
 ## Shared authentication
 
 All web consoles (Crashes, Tickets, Builder) share: