Add citation

I included everyone currently listed as a contributor (in alphabetical order) - happy to amend as needed.

README.md

@@ -118,4 +118,19 @@ The following hyperparameters were used during training:
 - Transformers 4.40.1
 - Pytorch 2.3.1
 - Datasets 2.18.0
-- Tokenizers 0.19.1
+- Tokenizers 0.19.1
+
+## Citation
+
+If you find NuminaMath-7B-TIR is useful in your work, please cite it with:
+
+```
+@misc{numina_math_7b,
+  author = {Edward Beeching and Costa Huang and Albert Jiang and Jia Li and Benjamin Lipkin and Zihan Qina and Kashif Rasul and Ziju Shen and Roman Soletskyi and Lewis Tunstall},
+  title = {NuminaMath 7B TIR},
+  year = {2024},
+  publisher = {Numina & Hugging Face},
+  journal = {Hugging Face repository},
+  howpublished = {\url{https://huggingface.co/AI-MO/NuminaMath-7B-TIR}}
+}
+```