add rtd conf env

CHANGELOG.md

 Latest Changes
 ==============
-Compiled on: Mon Jan  6 23:44:59 CET 2014
+Compiled on: Mon Jan  6 23:50:32 CET 2014
 
-    * 57e9bcf - (HEAD, origin/master, origin/HEAD, master) Fix #221 - not correctly inheriting some permissions, save() called on URLPath object instead of Article object! (6 minutes ago) <benjaoming>
+    * 2eaf23e - (HEAD, tag: alpha/0.0.23, origin/master, origin/HEAD, master) Bump to 0.0.23 (5 minutes ago) <benjaoming>
+    * 57e9bcf - Fix #221 - not correctly inheriting some permissions, save() called on URLPath object instead of Article object! (12 minutes ago) <benjaoming>
     *   489f2c5 - Merge pull request #220 from Russell-Jones/master (7 days ago) <benjaoming>
     |\  
     | * d36dbed - Add try catch block to test for and use if available new in 1.6 db transaction API (7 days ago) <Russell Jones>

docs/conf.py

@@ -109,6 +109,12 @@ pygments_style = 'sphinx'
 # a list of builtin themes.
 html_theme = 'default'
 
+on_rtd = os.environ.get('READTHEDOCS', None) == 'True'
+if on_rtd:
+    html_theme = 'default'
+else:
+    html_theme = 'nature'
+
 # Theme options are theme-specific and customize the look and feel of a theme
 # further.  For a list of options available for each theme, see the
 # documentation.