small fix

app.py

@@ -104,7 +104,7 @@ def process_video(
             )
 
             detections.confidence = np.ones(len(detections))
-            detections.class_ids = np.zeros(len(detections))
+            detections.class_id = np.zeros(len(detections))
 
             detections = TRACKER.update_with_detections(detections)
             frame = annotate_image(