added postgres to backend pytest gitlab ci

.gitlab-ci.yml

@@ -35,6 +35,13 @@ backend-flake8:
 backend-pytest:
   stage: test
   image: python:3.6
+  services:
+    - name: postgres:11.3
+      alias: db
+  variables:
+    POSTGRES_USER: baserow
+    POSTGRES_PASSWORD: baserow
+    POSTGRES_DB: baserow
   script:
     - make install-backend-dependencies
     - export PYTHONPATH=$CI_PROJECT_DIR/backend/src

backend/src/baserow/config/settings/test.py

@@ -1 +1,13 @@
 from .base import *  # noqa: F403, F401
+
+
+DATABASES = {
+    'default': {
+        'ENGINE': 'django.db.backends.postgresql_psycopg2',
+        'NAME': 'baserow',
+        'USER': 'baserow',
+        'PASSWORD': 'baserow',
+        'HOST': 'db',
+        'PORT': '5432',
+    }
+}