Add installation hint

Signed-off-by: Knut Ahlers <knut@ahlers.me>

README.md

@@ -5,3 +5,23 @@
 My specific usecase for this is I do have accounts which OTP secrets are stored outside of my TOTP generator as usually I don't need to access those accounts and if I would add those secrets to my TOTP generator I would have a lot more entries in it. So I do store the secrets in a safe place and needed a convenient generator to generate single OTP tokens from them.
 
 ![](screenshot.png)
+
+## Installation
+
+Either use the provided Docker image:
+
+```console
+# docker run --rm -ti -p 3000:3000 luzifer/webtotp
+```
+
+Or compile the code yourself and just put the generated files somewhere:
+
+```console
+# npm ci && npm run build
+# tree dist
+dist
+├── app.js
+└── index.html
+
+0 directories, 2 files
+```