Fix toc

rtd/source/index.rst

diff --git a/rtd/source/index.rst b/rtd/source/index.rst
index d24d2c8..3972486 100644
--- a/rtd/source/index.rst
+++ b/rtd/source/index.rst
@@ -12,6 +12,8 @@
 .. warning:: We are in the process of changing documentation format as well as hosting mechanism.
              Please be patient with us as we migrate our entire documentation to this new setup.
 
+.. toctree::
+
 Introduction
 ------------