simplify entrypoint

src/main.rs

@@ -30,11 +30,10 @@ async fn main() {
         .nest_service("/assets", assets_svc)
         .route("/signup", get(get_signup).post(post_signup))
         .route("/signup_success/:receipt", get(signup_success))
-        .layer(session_layer);
+        .layer(session_layer)
+        .into_make_service();
 
     let addr = SocketAddr::from(([127, 0, 0, 1], 3000));
     let listener = tokio::net::TcpListener::bind(&addr).await.unwrap();
-    axum::serve(listener, app.into_make_service())
-        .await
-        .unwrap();
+    axum::serve(listener, app).await.unwrap();
 }