[docs] Publish releasenotes alongside docs to readthedocs

This patch set adds a relative symlink from docs/source/releasenotes
to releasenotes/source/ so that releasenotes can be published
to deckhand.readthedocs.io. A new tab link is added on the
documentation page which references Deckhand's release notes.

The command used to generate the symlink was:

    ln -rs releasenotes/source/ docs/source/releasenotes

Change-Id: I07058ca47ecc7b1fb211cae53aedc5f796542cff

docs/source/conf.py

@@ -34,7 +34,12 @@ extensions = [
     'sphinx.ext.autodoc',
     'sphinx.ext.todo',
     'sphinx.ext.viewcode',
-    'oslo_policy.sphinxpolicygen'
+    'oslo_policy.sphinxpolicygen',
+    # NOTE(fmontei): This is here so that readthedocs can publish releasenotes
+    # as well as documentation on the same domain and to do that we use a
+    # relative symlink to the releasenotes page, but the reno extension is
+    # also required for the build.
+    'reno.sphinxext'
 ]
 
 # oslo_policy.sphinxpolicygen options
@@ -63,16 +68,16 @@ author = u'Deckhand Authors'
 # built documents.
 #
 # The short X.Y version.
-version = u'0.1.0'
+version = u'0.1'
 # The full version, including alpha/beta/rc tags.
-release = u'0.1.0'
+release = u'0.1'
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.
 #
 # This is also used if you do content translation via gettext catalogs.
 # Usually you set "language" from the command line for these cases.
-language = None
+language = "en"
 
 # List of patterns, relative to source directory, that match files and
 # directories to ignore when looking for source files.
@@ -106,21 +111,6 @@ html_theme_path = [sphinx_rtd_theme.get_html_theme_path()]
 # so a file named "default.css" will overwrite the builtin "default.css".
 html_static_path = ['_static']
 
-# Custom sidebar templates, must be a dictionary that maps document names
-# to template names.
-#
-# This is required for the alabaster theme
-# refs: http://alabaster.readthedocs.io/en/latest/installation.html#sidebars
-html_sidebars = {
-    '**': [
-        'about.html',
-        'navigation.html',
-        'relations.html',  # needs 'show_related': True theme option to display
-        'searchbox.html',
-        'donate.html',
-    ]
-}
-
 
 # -- Options for HTMLHelp output ------------------------------------------
 

docs/source/index.rst

@@ -61,6 +61,14 @@ Developer's Guide
    policy-enforcement
    testing
 
+Release Notes
+=============
+
+.. toctree::
+   :maxdepth: 1
+
+   releasenotes/index.rst
+
 Glossary
 ========
 

docs/source/releasenotes

@@ -0,0 +1 @@
+../../releasenotes/source

releasenotes/source/conf.py

@@ -65,7 +65,7 @@ release = u'0.1'
 #
 # This is also used if you do content translation via gettext catalogs.
 # Usually you set "language" from the command line for these cases.
-# language = None
+language = "en"
 
 # List of patterns, relative to source directory, that match files and
 # directories to ignore when looking for source files.