adding license bagde

README.md

@@ -5,3 +5,16 @@ Here you will find all of the training resources used in the training session of
 * [Github training resources](https://github.com/open-phytoliths/ICOPS-training-2022/tree/main/Github)
   * Session 1 - Basic Github - slides and video link
   * Session 2 - Collaboration with Github - slides and video link  
+
+
+## License:
+Shield: [![CC BY 4.0][cc-by-shield]][cc-by]
+
+This work is licensed under a
+[Creative Commons Attribution 4.0 International License][cc-by].
+
+[![CC BY 4.0][cc-by-image]][cc-by]
+
+[cc-by]: http://creativecommons.org/licenses/by/4.0/
+[cc-by-image]: https://i.creativecommons.org/l/by/4.0/88x31.png
+[cc-by-shield]: https://img.shields.io/badge/License-CC%20BY%204.0-lightgrey.svg