Re-add docs env
diff --git a/tox.ini b/tox.ini
index a2b1d72..0ab4fd5 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-envlist = {pypy,py26,py27,py33,py34}{,-cryptographyMaster},pypi-readme,check-manifest,flake8,pyroma
+envlist = {pypy,py26,py27,py33,py34}{,-cryptographyMaster},pypi-readme,check-manifest,flake8,pyroma,docs
 
 [testenv]
 whitelist_externals =
@@ -43,3 +43,10 @@
     check-manifest
 commands =
     check-manifest
+
+[testenv:docs]
+deps =
+     sphinx==1.2.2
+basepython = python2.7
+commands =
+     sphinx-build -W -b html doc doc/_build/html