build: add GitHub workflow to build release image

.github/workflows/release.yml

@@ -0,0 +1,36 @@
+name: Create release and upload assets
+
+on:
+  push:
+    tags:
+      - 'v*'
+
+jobs:
+  build_image:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-java@v4
+        with:
+          java-version: '21'
+          distribution: 'temurin'
+
+      - name: Setup Gradle
+        uses: gradle/actions/setup-gradle@v3
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Login to Docker Hub
+        uses: docker/login-action@v3
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Execute image build and push
+        run: |
+          ./gradlew test bootBuildImage
+          docker tag ghcr.io/pcvolkmer/onco-analytics-monitor ghcr.io/pcvolkmer/onco-analytics-monitor:${{ github.ref_name }}
+          docker push ghcr.io/pcvolkmer/onco-analytics-monitor
+          docker push ghcr.io/pcvolkmer/onco-analytics-monitor:${{ github.ref_name }}