Add base model metadata to model card

It would be nice to trace the genealogy of merged models like this: https://colab.research.google.com/drive/1s2eQlolcI1VGgDhqWIANfkfKvcKrMyNr?usp=sharing

README.md

@@ -87,6 +87,9 @@ model-index:
       name: accuracy
 tags:
 - merge
+base_model:
+- teknium/OpenHermes-2.5-Mistral-7B
+- Intel/neural-chat-7b-v3-3
 ---
 ![image/png](https://cdn-uploads.huggingface.co/production/uploads/6468ce47e134d050a58aa89c/x44nNbPTpv0zGTqA1Jb2q.png)