How can i include the `genindex` in a Sphinx TOC?

Sphinx generates an index named genindex when building a documentation and therefore forbids to use that name for a document. Now, how would I include a link to that index in a table of contents?

I've tried this:

.. toctree::
   :maxdepth: 2

   genindex
   api


Indices and tables
==================

* :ref:`genindex`

While the last line does create a link to that index in the document, the build doesn't know the reference when creating the TOC:

WARNING: toctree contains reference to nonexisting document 'genindex'

Create a File genindex.rst with the following Content:

Index
=====

In your index.rst add:

.. toctree::
   :hidden:

   genindex

If you you also want to have the Link and Text "Index" on the Site and not only in the left Navigation then remove :hidden: