add license to intro page

Author: Andrew McCluskey

_build/intro.html

@@ -7,7 +7,7 @@
 next_page:
   url: /getting_started.html
 suffix: .md
-search: zenodo introduction python chemists doi org div contributing href xxxxxximg src badge xxxxxx svg class left style clear both please guidelines github com pythoninchemistry intropythonchemists blob master content md contribute
+search: org license href zenodo creativecommons introduction python chemists doi src div style contributing rel licenses creative commons xxxxxximg badge xxxxxx svg class left clear both please guidelines github com pythoninchemistry intropythonchemists blob master content md contribute img alt border width l x png abr work licensed under attribution international
 
 comment: "***PROGRAMMATICALLY GENERATED, DO NOT EDIT. SEE ORIGINAL FILES IN /content***"
 ---
@@ -22,6 +22,7 @@
 <h1 id="An-Introduction-to-Python-for-Chemists">An Introduction to Python for Chemists<a class="anchor-link" href="#An-Introduction-to-Python-for-Chemists"> </a></h1><p><a href="https://doi.org/10.5281/zenodo.xxxxxx"><img src="https://zenodo.org/badge/DOI/10.5281/zenodo.xxxxxx.svg" class="left"></a></p>
 <div style="clear:both;"></div><p>An Introduction to Python for Chemists</p>
 <p>Please look at the <a href="https://github.com/pythoninchemistry/intro_python_chemists/blob/master/content/contributing.md">contributing guidelines</a> if you would like to contribute.</p>
+<p><a rel="license" href="http://creativecommons.org/licenses/by/4.0/"><img alt="Creative Commons License" style="border-width:0" src="https://i.creativecommons.org/l/by/4.0/88x31.png" /></a><br />This work is licensed under a <a rel="license" href="http://creativecommons.org/licenses/by/4.0/">Creative Commons Attribution 4.0 International License</a>.</p>
 
 </div>
 </div>

content/intro.md

@@ -5,4 +5,6 @@
 
 An Introduction to Python for Chemists
 
-Please look at the [contributing guidelines](https://github.com/pythoninchemistry/intro_python_chemists/blob/master/content/contributing.md) if you would like to contribute.
+Please look at the [contributing guidelines](https://github.com/pythoninchemistry/intro_python_chemists/blob/master/content/contributing.md) if you would like to contribute.
+
+<a rel="license" href="http://creativecommons.org/licenses/by/4.0/"><img alt="Creative Commons License" style="border-width:0" src="https://i.creativecommons.org/l/by/4.0/88x31.png" /></a><br />This work is licensed under a <a rel="license" href="http://creativecommons.org/licenses/by/4.0/">Creative Commons Attribution 4.0 International License</a>.