Update RefererRedirect.md

docs/Component/RefererRedirect.md

@@ -9,6 +9,8 @@ This component uses a referer key in query string to redirect back to given refe
 The neat thing here is that it doesn't require changes to existing actions. This can just be
 added on top, for one or all controllers.
 
+Live demo: https://sandbox.dereuromark.de/sandbox/tools-examples/redirect-test
+
 ## Alternatives
 AN alternative is using hidden input fields, but that also requires a bit more logic in your controllers or component scope already.
 Hidden inputs, however, can lose their value on refresh, or if your browser restarts. So the safest bet is still to use query strings.