docs: Add description of 'oslopolicy-policy-generator'

Change-Id: I6c98efa7463fc71176f9635f6ffebb5c7050bd49
Signed-off-by: Stephen Finucane <sfinucan@redhat.com>

doc/source/cli/index.rst

@@ -51,6 +51,44 @@ with the plain member token
      --access sample_data/auth_v3_token_member.json \
      --rule compute_extension:flavorextraspecs:index
 
+oslopolicy-policy-generator
+===========================
+
+The ``oslopolicy-policy-generator`` command can be used to generate a policy
+file that shows the effective policy in use. This is generated by merging the
+registered defaults and policies loaded from a configuration file.
+
+Examples
+--------
+
+The generate the effective policy file for a namespace called ``keystone``:
+
+.. code-block:: bash
+
+   oslopolicy-policy-generator --namespace keystone
+
+To generate the effective policy file in JSON:
+
+.. code-block:: bash
+
+   oslopolicy-policy-generator --namespace keystone --format json
+
+To generate the effective policy file and output directly to a file:
+
+.. code-block:: bash
+
+   oslopolicy-policy-generator \
+     --namespace keystone \
+     --format yaml \
+     --output-file keystone-policy.yaml
+
+To show the additional options and arguments supported by
+``oslopolicy-policy-generator``:
+
+.. code-block:: bash
+
+   oslopolicy-policy-generator --help
+
 oslopolicy-sample-generator
 ===========================
 
@@ -67,12 +105,11 @@ To generate sample policies for a namespace called ``keystone``:
 
    oslopolicy-sample-generator --namespace keystone
 
-
 To generate sample policies in JSON use:
 
 .. code-block:: bash
 
-   oslopolicy-sample-generator --namespace nova --format json
+   oslopolicy-sample-generator --namespace keystone --format json
 
 To generate a sample policy file and output directly to a file: