add healthcheck endpoint and startup check

packages/backend/src/health/mod.rs

@@ -0,0 +1,3 @@
+mod routes;
+
+pub use routes::*;

packages/backend/src/health/routes.rs

@@ -0,0 +1,16 @@
+use actix_web::{get, web, HttpResponse, Responder, Scope};
+
+use crate::store;
+
+#[get("/")]
+async fn get_live() -> impl Responder {
+    if store::can_reach_redis() {
+        return HttpResponse::Ok();
+    } else {
+        return HttpResponse::ServiceUnavailable();
+    }
+}
+
+pub fn init() -> Scope {
+    web::scope("/live").service(get_live)
+}