update workflow

.github/workflows/main.yml

@@ -35,6 +35,12 @@ jobs:
     - name: Checkout code
       uses: actions/checkout@v2
 
+    - name: Login to Docker Hub
+      uses: docker/login-action@v1
+      with:
+        username: ${{ secrets.DOCKER_USERNAME }}
+        password: ${{ secrets.DOCKER_PASSWORD }}
+
     - name: Run tests
       run: |
         docker run --rm macrdel/sentiment-summarize-youtube-comments-backend-tests:latest pytest tests