added backend desc

README.md

@@ -3,5 +3,9 @@
 ## Up and Running
 To start developing use `docker-comse up` and if
 this was successful you can access the app on: 
-`localhost:8080`
+`localhost:8080`.
+
+To get the API working checkout: https://0xacab.org/jvoisin/mat2-web.git
+and run `docker-compose up` in that folder as well.
+This starts the backend on `localhost:8000`
 You can start hacking :)