Update app.py

app.py

@@ -9,7 +9,7 @@ from timeit import default_timer as timer
 from typing import Tuple, Dict
 
 # Setup class names
-with open(class_names.txt, 'r') as f:
+with open('class_names.txt', 'r') as f:
   class_names= [food_name.strip() for food_name in f.readlines()]