support ORPO

Former-commit-id: f44a4c27e2461cdaa1b16865f597a31033c0e6d9

data/README.md

@@ -34,6 +34,8 @@ If you are using a custom dataset, please provide your dataset definition in the
 
 Given above, you can use the custom dataset via specifying `--dataset dataset_name`.
 
+----
+
 Currently we support dataset in **alpaca** or **sharegpt** format, the dataset in alpaca format should follow the below format:
 
 ```json
@@ -84,6 +86,10 @@ For the preference datasets, the `response` column should be a string list whose
 }
 ```
 
+Remember to set `"ranking": true` for the preference datasets.
+
+----
+
 The dataset in sharegpt format should follow the below format:
 
 ```json