modify travis file

.travis.yml

@@ -2,6 +2,11 @@ language: python
 python:
     - 3.4
     - 3.5
-
 install: pip install -r requirements.dev.txt
-script: python manage.py test
+script: python manage.py test
+services:
+  - postgresql
+addons:
+  postgresql: "9.5"
+before_script:
+  - psql -c 'create database db;' -U postgres