Update README.md

README.md

@@ -60,7 +60,7 @@ logger - Get log file
 ```
 
 ## Tips
-* Run [one_time_indexer.py](one_time_indexer.py) file to save old files in the database that are not indexed yet.
+* Use `index` command or run [one_time_indexer.py](one_time_indexer.py) file to save old files in the database that are not indexed yet.
 * You can use `|` to separate query and file type while searching for specific type of file. For example: `Avengers | video`
 * If you don't want to create a channel or group, use your chat ID / username as the channel ID. When you send a file to a bot, it will be saved in the database.