Update README.md

added license information

Author: kthood

README.md

@@ -11,3 +11,7 @@ We welcome and recognize all contributions. You can see a list of current contri
 ## Credits
 
 This project is created using the excellent open source [Jupyter Book project](https://jupyterbook.org/) and the [executablebooks/cookiecutter-jupyter-book template](https://github.com/executablebooks/cookiecutter-jupyter-book).
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+## License
+
+This book is licensed under the [Creative Commons Attribution 4.0 International License](https://creativecommons.org/licenses/by/4.0/).