add github workflow for notification-service

.github/workflows/notification-service.yml

@@ -0,0 +1,37 @@
+name: Notification Service
+on:
+  push:
+    paths:
+      - notification-service/**
+    branches:
+      - '**'
+jobs:
+  build:
+    name: Build
+    runs-on: ubuntu-latest
+    env:
+      working-directory: ./notification-service
+      DOCKER_IMAGE_NAME: ${{ secrets.DOCKERHUB_USERNAME }}/bookstore-notification-service
+    defaults:
+      run:
+        working-directory: ${{ env.working-directory }}
+    steps:
+      - uses: actions/checkout@v4
+      - name: Setup Java 21
+        uses: actions/setup-java@v4
+        with:
+          java-version: '21'
+          distribution: 'temurin'
+          cache: 'maven'
+      - name: Build with Maven
+        run: ./mvnw -ntp verify
+      - name: Login to Docker Hub
+        uses: docker/login-action@v3
+        with:
+          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+      - name: Build and Publish Docker Image
+        run: |
+          ./mvnw spring-boot:build-image -DskipTests
+          echo "Pushing the image $DOCKER_IMAGE_NAME to Docker Hub."
+          docker push $DOCKER_IMAGE_NAME