added link to documentation in the readme (#48)

* added link to documentation in the readme

* Added link to the source code in the docs

Author: lenzip

README.md

@@ -6,3 +6,7 @@ guidelines available at https://cms-analysis.docs.cern.ch/guidelines/plotting/ge
 ```
 pip install cmsstyle
 ```
+
+## Documentation
+
+Documentation is available at [cmsstyle.readthedocs.io](https://cmsstyle.readthedocs.io/).

docs/index.md

@@ -5,3 +5,5 @@ The `cmsstyle` library provides a pyROOT-based implementation of the figure guid
 For additional information on CMS plot-style recommendations,
 please see the
 [CMS-internal documentation](https://cms-analysis.docs.cern.ch/).
+
+The source code is available on [github](https://github.com/cms-cat/cmsstyle).