Update app.py

app.py

@@ -13,7 +13,7 @@ def load_all_usernames(filename):
 
     with gzip.open(filepath, 'r') as f:
         usernames = f.read().decode('utf-8')
-    usernames = ujson.loads(usernames)
+    usernames = json.loads(usernames)
 
     return usernames