Add Django 1.8 alpha to test matrix

.travis.yml

@@ -21,6 +21,10 @@ env:
     - TOX_ENV=py26-django15
     - TOX_ENV=py27-django14
     - TOX_ENV=py26-django14
+    - TOX_ENV=py34-django18alpha
+    - TOX_ENV=py33-django18alpha
+    - TOX_ENV=py32-django18alpha
+    - TOX_ENV=py27-django18alpha
     - TOX_ENV=py34-djangomaster
     - TOX_ENV=py33-djangomaster
     - TOX_ENV=py32-djangomaster
@@ -29,6 +33,10 @@ env:
 matrix:
   fast_finish: true
   allow_failures:
+    - env: TOX_ENV=py34-django18alpha
+    - env: TOX_ENV=py33-django18alpha
+    - env: TOX_ENV=py32-django18alpha
+    - env: TOX_ENV=py27-django18alpha
     - env: TOX_ENV=py34-djangomaster
     - env: TOX_ENV=py33-djangomaster
     - env: TOX_ENV=py32-djangomaster

tox.ini

@@ -3,7 +3,7 @@ envlist =
        py27-{flake8,docs},
        {py26,py27}-django14,
        {py26,py27,py32,py33,py34}-django{15,16},
-       {py27,py32,py33,py34}-django{17,master}
+       {py27,py32,py33,py34}-django{17,18alpha,master}
 
 [testenv]
 commands = ./runtests.py --fast
@@ -14,6 +14,7 @@ deps =
        django15: Django==1.5.6  # Should track minimum supported
        django16: Django==1.6.3  # Should track minimum supported
        django17: Django==1.7.2  # Should track maximum supported
+       django18alpha: https://www.djangoproject.com/download/1.8a1/tarball/
        djangomaster: https://github.com/django/django/zipball/master
        {py26,py27}-django{14,15,16,17}: django-guardian==1.2.3
        {py26,py27}-django{14,15,16}: oauth2==1.5.211