Update README.md

Add langchain reference

README.md

@@ -95,3 +95,10 @@ generated_text = tokenizer.decode(
     skip_special_tokens=True
 )
 ```
+
+## Example of RAG with Langchain
+
+[This reference](https://huggingface.co/Mike0307/text2vec-base-chinese-rag#example-of-langchain-rag) shows how to customize langchain llm with this phi-3 lora model.
+
+![image/png](https://cdn-uploads.huggingface.co/production/uploads/6414866f1cbd604c9217c7d0/RrBoHJINfrSWtCNkePs7g.png)
+