Added missing link to readme
@@ -10,6 +10,7 @@ This directory contains all the notebooks built as part of the
* ``getting_started``: Notebooks used in the [getting started](http://holoviews.org/getting_started/index.html) guide.
* `reference`: Notebooks shown in the website [reference gallery](http://holoviews.org/reference/index.html)
* ``topics``: Notebooks shown in the [showcase](http://holoviews.org/reference/showcase/index.html)
+* ``user_guide``: Notebooks used in the [user guide](http://holoviews.org/user_guide/index.html).
## Contributing to examples
