Add to nwb-overview website from the frontpage of the docs (#1531)

Co-authored-by: Ben Dichter <[email protected]>

docs/source/index.rst

@@ -7,7 +7,9 @@ NWB for Python
 ==============
 
 PyNWB is a Python package for working with NWB files. It provides a high-level API for
-efficiently working with Neurodata stored in the `NWB format <https://nwb-schema.readthedocs.io>`_.
+efficiently working with neurodata stored in the NWB format. If you are new to NWB
+and would like to learn more, then please also visit the :nwb_overview:`NWB Overview <>`
+website, which provides an entry point for researchers and developers interested in using NWB.
 
 `Neurodata Without Borders (NWB) <http://www.nwb.org/>`_ is a project to develop a
 unified data format for cellular-based neurophysiology data, focused on the