Add gateway push to dokerhub

.github/workflows/main.yml

@@ -99,4 +99,23 @@ jobs:
         with:
           context: ./frontend/
           push: true
-          tags: failwiz/taski_frontend:latest
+          tags: failwiz/taski_frontend:latest
+  build_gateway_and_push_to_docker_hub:
+    name: Push gateway Docker image to DockerHub
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out the repo
+        uses: actions/checkout@v3
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v2
+      - name: Login to Docker 
+        uses: docker/login-action@v2
+        with:
+          username: ${{ secrets.DOCKER_USERNAME }}
+          password: ${{ secrets.DOCKER_PASSWORD }}
+      - name: Push to DockerHub
+        uses: docker/build-push-action@v4
+        with:
+          context: ./gateway/
+          push: true
+          tags: failwiz/taski_gateway:latest