Add database service to ci

.github/workflows/test.yaml

@@ -7,9 +7,18 @@ on:
 jobs:
     test:
         runs-on: ubuntu-latest
+
+        services:
+            mongodb:
+                image: mongo:6.0
+                ports:
+                    - 27017:27017
+
         steps:
             - uses: actions/checkout@v2
             - name: Install dependencies
               run: npm install
             - name: Run tests
               run: npm test
+              env:
+                  MONGODB_URI: mongodb://localhost:27017/Twitter