Add sample policy file to documentation

Now that Zun has all of its policies registered in code, we can
generate samples to publish in documentation.

bp policy-and-docs-in-code

Change-Id: I8b8efe9bf0af5aef39e293a9ddf9a79da35e5f8f

doc/source/conf.py

@@ -25,6 +25,8 @@ extensions = [
     'sphinx.ext.graphviz',
     'openstackdocstheme',
     'oslo_config.sphinxconfiggen',
+    'oslo_policy.sphinxext',
+    'oslo_policy.sphinxpolicygen',
 ]
 
 # autodoc generation is a bit aggressive and a nuisance when doing heavy
@@ -45,6 +47,9 @@ bug_tag = ''
 config_generator_config_file = '../../etc/zun/zun-config-generator.conf'
 sample_config_basename = '_static/zun'
 
+policy_generator_config_file = '../../etc/zun/zun-policy-generator.conf'
+sample_policy_basename = '_static/zun'
+
 # General information about the project.
 project = u'zun'
 copyright = u'2013, OpenStack Foundation'

doc/source/configuration/index.rst

@@ -5,3 +5,4 @@ Sample Configuration File
     :maxdepth: 1
 
     sample-config
+    policy

doc/source/configuration/policy.rst

@@ -0,0 +1,12 @@
+====================
+Policy configuration
+====================
+
+Configuration
+~~~~~~~~~~~~~
+
+The following is an overview of all available policies in Zun. For a sample
+configuration file.
+
+.. show-policy::
+   :config-file: ../../etc/zun/zun-policy-generator.conf