Adding instructions on how to setup a Jenkins node to run VOLTHA pipelines

Change-Id: I4219f754065c52e8c0ac61acadfb33d8f133a26e
diff --git a/index.rst b/index.rst
index 8c51b20d..64b6edf 100644
--- a/index.rst
+++ b/index.rst
@@ -121,6 +121,7 @@
    overview/workflows.rst
    overview/operate.rst
    overview/lab_setup.rst
+   overview/jenkins_node.rst
    overview/troubleshooting.rst
    overview/releases.rst
    overview/contributing.rst