feat: add environment variable support and update README instructions

main.py

@@ -183,7 +183,12 @@ if __name__ == '__main__':
 
     signal.signal(signal.SIGINT, lambda signum, frame: interrupt_handler(signum, driver))
     
-    setupStats(driver, "https://tube.kobim.cloud/w/iN2T8PmbSb4HJTDA2rV3sg")
+    url = os.getenv('VIDEO_URL')
+    if url is None:
+        logger.error('VIDEO_URL environment variable is not set.')
+        raise SystemExit(1)
+    
+    setupStats(driver, url)
     
     logger.log(logging.INFO, 'Starting server collector.')
     httpd = HTTPServer(('collector', 9092), partial(Handler, downloadStats, driver, logger))