diff --git a/README.md b/README.md
index 809623f..6a7773c 100644
--- a/README.md
+++ b/README.md
@@ -9,3 +9,9 @@ make build && make run
 ```
 
 Then open your browser at [localhost:8080](http://localhost:8080).
+
+## Description
+
+The `make build` command executes a `docker build`. The Dockerfile uses the official Go 1.11 image
+* to compile `play.go` into wasm
+* to compile `serve/serve.go` into the web server that will serve the files.