VOLTHA releasing process documentation

Change-Id: I695567782e7abf41c122d43c9618f3340cb43dd5
diff --git a/index.rst b/index.rst
index 7a94b76..dffd547 100644
--- a/index.rst
+++ b/index.rst
@@ -123,6 +123,7 @@
    overview/lab_setup.rst
    overview/troubleshooting.rst
    overview/releases.rst
+   overview/release_process.rst
    overview/contributing.rst
 
 .. toctree::