Test on newer versions of postgres

Author: gavinwahl

.travis.yml

@@ -8,10 +8,17 @@ env:
   - DATABASE_URL=postgres:///json_test
 services:
   - postgresql
-addons:
-  postgresql: "9.4"
-  apt:
-    packages:
-      - postgresql-server-dev-9.4
+matrix:
+  include:
+    - addons:
+        postgresql: "9.5"
+        apt:
+          packages:
+            - postgresql-server-dev-9.5
+    - addons:
+        postgresql: "9.6"
+        apt:
+          packages:
+            - postgresql-server-dev-9.6
 script: python test.py
 language: python