Add Github link, set proper license

This PR adds the Github repository link and sets the proper license according to the Github README.

README.md

@@ -1,6 +1,6 @@
 ---
 library_name: transformers
-license: other
+license: apache-2.0
 base_model: meta-llama/Llama-3.1-8B
 tags:
 - llama-factory
@@ -19,6 +19,8 @@ This model is based on the paper [GuardReasoner: Towards Reasoning-based LLM Saf
 
 The training data of R-SFT can be found in [GuardReasonerTrain](https://huggingface.co/datasets/yueliu1999/GuardReasonerTrain).
 
+Code can be found at: https://github.com/yueliu1999/GuardReasoner/.
+
 # Usage
 ```
 import re
@@ -68,7 +70,6 @@ Mark
 output = post_process(generate(vllm_model, prompt_list, response_list)[0].outputs[0].text)
 
 print(output)
-
 ```
 
 # Citation