Add docker build/push

.github/workflows/ci.yml

@@ -17,3 +17,28 @@ jobs:
           cache: maven
       - name: Build and test
         run: mvn -B verify
+
+  docker:
+    runs-on: ubuntu-latest
+    needs: build
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Log in to Docker Hub
+        if: github.event_name == 'push' && github.ref == 'refs/heads/main'
+        uses: docker/login-action@v3
+        with:
+          username: kruhlmann
+          password: ${{ secrets.DOCKER_HUB_ACCESS_TOKEN }}
+
+      - name: Build and push Docker image
+        uses: docker/build-push-action@v5
+        with:
+          context: .
+          push: ${{ github.event_name == 'push' && github.ref == 'refs/heads/main' }}
+          tags: |
+            kruhlmann/imgfloat-j:latest
+            kruhlmann/imgfloat-j:${{ github.sha }}