update readme

README.md

@@ -24,4 +24,22 @@ python -m chebai fit --config=[path-to-your-tox21-config] --trainer.callbacks=co
 
 ```
 python -m chebai train --config=[path-to-your-tox21-config] --trainer.callbacks=configs/training/default_callbacks.yml  --ckpt_path=[path-to-model-with-ontology-pretraining]
-```
+```
+
+## Features on branch `features-sfluegel`
+### Cross-validation
+Use inner cross-validation by not splitting between test and validation sets at dataset creation, 
+but using k-fold cross-validation at runtime. This creates k models with separate metrics and checkpoints.
+For training with `k`-fold cross-validation, use the `cv-fit` subcommand and the options
+```
+--data.init_args.inner_k_folds=k --n_splits=k
+```
+### Chebi versions
+Change the chebi version used for all sets (default: 200):
+```
+--data.init_args.chebi_version=VERSION
+```
+To change only the version of the train and validation sets independently of the test set, use
+```
+--data.init_args.chebi_version_train=VERSION
+```