Updating to run against multiple Django versions.

Author: cyface

.travis.yml

@@ -3,6 +3,10 @@ python:
 - '2.7.11'
 - '3.5.1'
 cache: pip
+env:
+    matrix:
+        - DJANGO="Django<1.9,>=1.8"
+        - DJANGO="Django<1.10,>=1.9"
 install:
 - pip install -r x_robots_tag_middleware_demo/requirements_dev.txt
 script: coverage run --source=x_robots_tag_middleware,x_robots_tag_middleware_demo