Fix markup to be compatible with Sphinx and add rough API doc
diff --git a/doc/index.rst b/doc/index.rst
index c2aa3f5..fd79546 100644
--- a/doc/index.rst
+++ b/doc/index.rst
@@ -11,6 +11,8 @@
 .. toctree::
    :maxdepth: 2
 
+   api
+
 Indices and tables
 ==================