Check config on load (#4170)

Co-authored-by: syuilo <syuilotan@yahoo.co.jp>

src/db/redis.ts

@@ -1,10 +1,8 @@
 import * as redis from 'redis';
 import config from '../config';
 
-export default config.redis ? redis.createClient(
-	config.redis.port,
-	config.redis.host,
-	{
-		auth_pass: config.redis.pass
-	}
-) : null;
+export default config.redis.map(({ host, port, pass }) => {
+	return redis.createClient(port, host, {
+		auth_pass: pass.getOrElse(null)
+	});
+}).getOrElse(null);