Pin django version in tox docs

docs/conf.py

@@ -20,8 +20,9 @@ import shlex
 # add these directories to sys.path here. If the directory is relative to the
 # documentation root, use os.path.abspath to make it absolute, like shown here.
 #sys.path.insert(0, os.path.abspath('.'))
-sys.path.insert(0, os.path.abspath('..'))
-sys.path.insert(0, os.path.abspath('../tests'))
+parent = os.path.abspath(os.path.dirname(os.path.dirname(__file__)))
+sys.path.insert(0, parent)
+sys.path.insert(0, os.path.join(parent, 'tests'))
 
 import cms_helper
 import djangocms_blog

requirements-docs.txt

@@ -0,0 +1,3 @@
+-r requirements-test.txt
+Django<2.0
+html5lib<0.99999999

tox.ini

@@ -47,9 +47,7 @@ skip_install = true
 deps =
     sphinx
     sphinx-rtd-theme
-    html5lib<0.99999999
-    Django>=1.9,<1.10
-    -rrequirements-test.txt
+    -rrequirements-docs.txt
 changedir=docs
 skip_install = true
 commands=