Create postrges service for CI

.github/workflows/build-and-test.yml

@@ -7,6 +7,27 @@ on:
 jobs:
   test:
     runs-on: ubuntu-latest
+    services:
+      postgres:
+        image: postgres
+        env:
+          POSTGRES_USER: postgres
+          POSTGRES_PASSWORD: ""
+          POSTGRES_DB: postgres
+        ports:
+          - 5432:5432
+        # needed because the postgres container does not provide a healthcheck
+        # tmpfs makes DB faster by using RAM
+        options: >-
+          --mount type=tmpfs,destination=/var/lib/postgresql/data
+          --health-cmd pg_isready
+          --health-interval 10s
+          --health-timeout 5s
+          --health-retries 5
+    env:
+      RAILS_ENV: test
+      PGHOST: localhost
+      PGUSER: postgres
     steps:
       - uses: actions/checkout@v2
       - name: Set up Ruby
@@ -15,5 +36,8 @@ jobs:
           bundler-cache: true
       - name: Install dependencies
         run: bundle install
+      - name: Create DB
+        run: |
+          bin/rails db:prepare
       - name: Run tests
         run: bundle exec rake