Smaller requirements.txt since we rely on another file to setup sphinx as on RTD

docs/dev/build_the_docs.rst

+Build the documentation locally
+===============================
+
+Python environment
+------------------
+
+The manual is written in RestructuredText_ and is built with Sphinx_. It
+relies on a number of Python modules.
+
+Locally, install these two requirements file:
+
+* https://github.com/Ensembl/python-requirements/blob/master/readthedocs/requirements.txt
+* https://github.com/Ensembl/ensembl-hive/blob/master/requirements.txt
+
+On the EBI farm, those are already installed and you only need to activate
+the `ehive_sphinx` environment with ``pyenv local ehive_sphinx``.
+
+Other dependencies
+------------------
+
+* Doxygen_ to build the API documentation
+* a checkout of the Ensembl `Core API`_, with ``PERL5LIB`` set, to enable
+  the Perl Doxygen filter
+* Graphviz_ to generate the database diagrams
+* Pandoc_ to convert the POD HTML to RestructuredText
+
+Build process
+-------------
+
+Once you have all the above dependencies, go to ``ensembl-hive/docs``,
+run ``make html`` and open ``_build/html/index.html``.
+
+``make clean`` will cleanup all of ``_build/`` except the Doxygen
+documentation, since it takes quite a lot of time to generate. Run ``make
+cleaner`` to clean it up as well.
+
+
+.. _RestructuredText: http://docutils.sourceforge.net/rst.html
+.. _Sphinx: http://www.sphinx-doc.org/en/stable/
+.. _Doxygen: http://www.stack.nl/~dimitri/doxygen/
+.. _Graphviz: http://www.graphviz.org/
+.. _Pandoc: https://pandoc.org/
+.. _Core API: https://github.com/Ensembl/ensembl

docs/index.rst

@@ -91,8 +91,10 @@ Developer documentation
 =======================
 
 .. toctree::
+   :caption: Developer documentation
 
    dev/release_checklist
+   dev/build_the_docs
 
 
 Indices and tables

requirements.txt

-sphinx-rtd-theme
-sphinx
-recommonmark
 sphinxcontrib-doxylink