add training guide link in readme

README.md

@@ -142,6 +142,10 @@ print(f'Onnx-support/Total Models: {len(onnx_list)}/{len(full_list)}')
 
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+## Fine-tune
+To fine-tune this operator, please refer to [this example guide](https://github.com/towhee-io/examples/blob/main/fine_tune/5_train_cub_200_2011.ipynb).  
+
+
 ## Towhee Serve
 
 Models which is supported the towhee.serve.