Add server_port setting to example .env

See hydephp/framework#560

Author: caendesilva

.env.example

@@ -3,3 +3,6 @@
 
 # If you want to use Torchlight.dev, enter your API token here to automatically enable it
 # TORCHLIGHT_TOKEN=torch_
+
+# If you want to change the default port of the realtime compiler server, you can do so here
+# SERVER_PORT=8080