Add library name, pipeline tag, link to Github

This PR improves the model card by adding the `library_name` and `pipeline_tag`, and links to the Github repository. This ensures:
- The model can be easily found when searching by pipeline tag (https://huggingface.co/models?pipeline_tag=text-generation&sort=trending).
- The "Use in Transformers" widget appears on the model page.

README.md

@@ -1,9 +1,14 @@
 ---
 license: mit
+library_name: transformers
+pipeline_tag: text-generation
 ---
-The base Qwen2.5-Math-7B model used by LUFFY. 
+
+The base Qwen2.5-Math-7B model used by LUFFY, described in [Learning to Reason under Off-Policy Guidance](https://huggingface.co/papers/2504.14945). 
 We change to rope_theta from 10000 to 40000 and extend the context window to 16k.
-Also, we modify the chat_template for the system prompt and add <think>. 
+Also, we modify the chat_template for the system prompt and add <think>.
+
+Github: https://github.com/ElliottYan/LUFFY
 
 # Citation
 If you find our model, data, or evaluation code useful, please kindly cite our paper: