Try to fix the threading

Add explicit tokio::spawn in controller
Add an arbiter for the app_state in core

emgauwa-core/src/main.rs

@@ -1,6 +1,6 @@
 use std::net::TcpListener;
 
-use actix::Actor;
+use actix::{Actor, Arbiter};
 use actix_cors::Cors;
 use actix_web::middleware::TrailingSlash;
 use actix_web::{middleware, web, App, HttpServer};
@@ -32,7 +32,17 @@ async fn main() -> Result<(), std::io::Error> {
 		.map_err(EmgauwaError::from)?;
 	conn.close().await.map_err(EmgauwaError::from)?;
 
-	let app_state = AppState::new(pool.clone()).start();
+	let app_state_arbiter = Arbiter::with_tokio_rt(|| {
+		tokio::runtime::Builder::new_multi_thread()
+			.worker_threads(2)
+			.enable_all()
+			.build()
+			.unwrap()
+	});
+	let app_state_pool = pool.clone();
+	let app_state = Actor::start_in_arbiter(&app_state_arbiter.handle(), move |_| {
+		AppState::new(app_state_pool.clone())
+	});
 
 	log::info!(
 		"Starting server on {}:{}",