docs: trust schema spec

Refs: #2829

Change-Id: Idd41b49f41ee9e87ded8df2bb800a7a28bb69932
diff --git a/docs/index.rst b/docs/index.rst
index eaa0cb7..c058523 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -34,6 +34,7 @@
    + :doc:`tutorials/security-validator-config`
    + :doc:`tutorials/signed-interest`
    + :doc:`tutorials/certificate-format`
+   + :doc:`tutorials/security-trust-schema`
 
 - :doc:`manpages`