update readme

Author: ManfredLange

README.md

@@ -18,3 +18,16 @@ php -S localhost:3000
 ```
 
 Then point the browser to `localhost:3000`.
+
+# Prerequisites
+
+You need the following prerequisites on your computer:
+
+1. VS Code
+2. Docker Desktop (MacOS, Windows) or docker engine (Linux)
+3. VS Code extension for remote development
+4. git client
+
+With this setup VS Code will suggest re-opening in the dev container when you open the repo's local clone's directory in VS Code.
+
+Other setups may work as well but were not considered for this sample repository.