Add citation for model garden

PiperOrigin-RevId: 330542645

official/README.md

@@ -146,3 +146,17 @@ pip3 install --user -r official/requirements.txt
 ## Contributions
 
 If you want to contribute, please review the [contribution guidelines](https://github.com/tensorflow/models/wiki/How-to-contribute).
+
+## Citing TF Official Model Garden
+
+To cite this repository:
+
+```
+@software{tfmodels2020github,
+  author = {Chen Chen and Xianzhi Du and Le Hou and Jaeyoun Kim and Pengchong
+  Jin and Jing Li and Yeqing Li and Abdullah Rashwan and Hongkun Yu},
+  title = {TensorFlow Official Model Garden},
+  url = {https://github.com/tensorflow/models/tree/master/official},
+  year = {2020},
+}
+```