Allow filtering chat ids

env.sample.php

@@ -5,3 +5,4 @@
 $bot_api_key  = '1234567890:Telegram_bot_api_key';
 $bot_username = 'telegram_bot_username';
 $hook_url     = 'https://my.server.com/path/to/hook.php';
+$allowed_chat_ids = [123, 456]; // Set to empty array to allow message from any chat