update README

Author: motdotla

README.md

@@ -3,6 +3,8 @@
 # dotenv [![NPM version](https://img.shields.io/npm/v/dotenv.svg?style=flat-square)](https://www.npmjs.com/package/dotenv) [![downloads](https://img.shields.io/npm/dw/dotenv)](https://www.npmjs.com/package/dotenv)
 
 > Dotenv is a zero-dependency module that loads environment variables from a `.env` file into [`process.env`](https://nodejs.org/docs/latest/api/process.html#process_process_env). Storing configuration in the environment separate from code is based on [The Twelve-Factor App](https://12factor.net/config) methodology.
+>
+> [2 minute tutorial 📺](https://www.youtube.com/watch?v=YtkZR0NFd1g)
 
 ### Quickstart