add code tag and model description

I added a `code` tag to easily find the model among other models as well as a model description.

README.md

@@ -1,3 +1,26 @@
 ---
+language: code
 license: apache-2.0
+
 ---
+# CodeReviewer
+
+## Model description
+
+CodeReviewer is a model pre-trained with code change and code review data to support code review tasks.
+
+[CodeReviewer: Pre-Training for Automating Code Review Activities.](https://arxiv.org/abs/2203.09095) Zhiyu Li, Shuai Lu, Daya Guo, Nan Duan, Shailesh Jannu, Grant Jenks, Deep Majumder, Jared Green, Alexey Svyatkovskiy, Shengyu Fu, Neel Sundaresan.
+[GitHub](https://github.com/microsoft/CodeBERT/tree/master/CodeReviewer)
+
+## Citation
+
+If you user CodeReviewer, please consider citing the following paper:
+
+```
+@article{li2022codereviewer,
+  title={CodeReviewer: Pre-Training for Automating Code Review Activities},
+  author={Li, Zhiyu and Lu, Shuai and Guo, Daya and Duan, Nan and Jannu, Shailesh and Jenks, Grant and Majumder, Deep and Green, Jared and Svyatkovskiy, Alexey and Fu, Shengyu and others},
+  journal={arXiv preprint arXiv:2203.09095},
+  year={2022}
+}
+```