Fix demo task, which is useful for manual tests.

Rotefile

@@ -35,8 +35,9 @@ end)
 --end)
 
 desc("Demos Rookeries in a browser")
-task ("demo", {"start"}, function ()
-    exec("python", "-m", "webbrowser", "-n", "http://localhost:5000/")
+task ("demo", function ()
+    exec("docker-compose", "up", "-d", "--remove-orphans")
+    exec("python", "-m", "webbrowser", "-n", "http://localhost:3000/")
 end)
 
 desc("Starts Rookeries")