feat(example): added an example of packaging a rust app from github (#124)

* better caching when building docker images for app

Reviewed-on: #124
Reviewed-by: johnride <jg@nationtech.io>
Co-authored-by: Willem <wrolleman@nationtech.io>
Co-committed-by: Willem <wrolleman@nationtech.io>

examples/application_monitoring_with_tenant/src/main.rs

@@ -30,6 +30,7 @@ async fn main() {
         domain: Url::Url(url::Url::parse("https://rustapp.harmony.example.com").unwrap()),
         project_root: PathBuf::from("./examples/rust/webapp"),
         framework: Some(RustWebFramework::Leptos),
+        service_port: 3000,
     });
 
     let webhook_receiver = WebhookReceiver {