Merge "Add tenant project group definition example and definition in the doc"
diff --git a/doc/source/admin/tenants.rst b/doc/source/admin/tenants.rst
index 48e7ba8..5bcd2a2 100644
--- a/doc/source/admin/tenants.rst
+++ b/doc/source/admin/tenants.rst
@@ -25,7 +25,7 @@
 ------
 
 A tenant is a collection of projects which share a Zuul
-configuration.  An example tenant definition is:
+configuration. Some examples of tenant definitions are:
 
 .. code-block:: yaml
 
@@ -46,6 +46,27 @@
              - project2:
                  exclude-unprotected-branches: true
 
+.. code-block:: yaml
+
+   - tenant:
+       name: my-tenant
+       source:
+         gerrit:
+           config-projects:
+             - common-config
+           untrusted-projects:
+             - exclude:
+                 - job
+                 - semaphore
+                 - project
+                 - project-template
+                 - nodeset
+                 - secret
+               projects:
+                 - project1
+                 - project2:
+                     exclude-unprotected-branches: true
+
 .. attr:: tenant
 
    The following attributes are supported:
@@ -157,6 +178,24 @@
             processed. Defaults to the tenant wide setting of
             exclude-unprotected-branches.
 
+      .. attr:: <project-group>
+
+         The items in the list are dictionaries with the following
+         attributes. A **configuration items** definition is applied
+         to the list of projects.
+
+         .. attr:: include
+
+            A list of **configuration items** that should be loaded.
+
+         .. attr:: exclude
+
+            A list of **configuration items** that should not be loaded.
+
+         .. attr:: projects
+
+            A list of **project** items.
+
    .. attr:: max-nodes-per-job
       :default: 5