docs: trust schema spec

Refs: #2829

Change-Id: Idd41b49f41ee9e87ded8df2bb800a7a28bb69932
diff --git a/docs/tutorials.rst b/docs/tutorials.rst
index d4bc089..1583394 100644
--- a/docs/tutorials.rst
+++ b/docs/tutorials.rst
@@ -9,3 +9,4 @@
    tutorials/security-validator-config
    tutorials/signed-interest
    tutorials/certificate-format
+   tutorials/security-trust-schema