diff --git a/README.md b/README.md
index 836fd95c..87322e1c 100644
--- a/README.md
+++ b/README.md
@@ -46,6 +46,8 @@ $ vim .env
 # Start the dockers
 $ docker-compose up
 ```
+[What is the `.env` file?](https://docs.docker.com/compose/env-file/)
+
 
 ## Overview Video