Follow the new PTI for building docs

For compliance with the Project Testing Interface as described in:
https://governance.openstack.org/tc/reference/project-testing-interface.html#documentation
http://lists.openstack.org/pipermail/openstack-dev/2017-December/125710.html
http://lists.openstack.org/pipermail/openstack-dev/2018-March/128594.html

Change-Id: I86d2460231d246005cfdace75c50dc54c137f0ca

doc/source/conf.py

@@ -32,7 +32,7 @@ sys.path.insert(0, os.path.abspath('./'))
 # extensions coming with Sphinx (named 'sphinx.ext.*') or your custom ones.
 extensions = [
     'oslo_config.sphinxext',
-    'sphinx.ext.autodoc',
+    'sphinxcontrib.apidoc',
     'sphinx.ext.viewcode',
     'sphinxcontrib.httpdomain',
     'sphinxcontrib.pecanwsme.rest',
@@ -55,6 +55,18 @@ sample_config_basename = 'watcher'
 # text edit cycles.
 # execute "export SPHINX_DEBUG=1" in your terminal to disable
 
+# sphinxcontrib.apidoc options
+apidoc_module_dir = '../../watcher'
+apidoc_output_dir = 'api'
+apidoc_excluded_paths = [
+    'tests/*',
+    'db',
+    'decision_engine',
+    'doc',
+    'objects',
+]
+apidoc_separate_modules = True
+
 # The suffix of source filenames.
 source_suffix = '.rst'