Adding voltctl page downloading the README from opencord/voltctl

Change-Id: I3ed6218273c65498cb704d3048c38b49c2321da8
diff --git a/git_refs b/git_refs
index 1aba496..8fa142d 100644
--- a/git_refs
+++ b/git_refs
@@ -18,3 +18,4 @@
 voltha-openonu-adapter  /        master
 voltha-protos           /        master
 voltha-system-tests     /        master
+voltctl                 /        master
diff --git a/index.rst b/index.rst
index 056bb95..b22db7e 100644
--- a/index.rst
+++ b/index.rst
@@ -13,6 +13,13 @@
    overview/*
 
 .. toctree::
+   :maxdepth: 1
+   :caption: Voltctl
+   :glob:
+
+   voltctl
+
+.. toctree::
    :maxdepth: 2
    :caption: BBSim