Add dockerfile and workflow

.github/workflows/docker.yml

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+name: Publish Docker image
+
+on:
+  push:
+    branches:
+      - 'main'
+      - 'develop'
+
+jobs:
+  push_to_registry:
+    name: Push Docker image to Docker Hub
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out the repo
+        uses: actions/checkout@v3
+
+      - name: Log in to Docker Hub
+        uses: docker/login-action@f054a8b539a109f9f41c372932f1ae047eff08c9
+        with:
+          username: ${{ secrets.DOCKER_USERNAME }}
+          password: ${{ secrets.DOCKER_PASSWORD }}
+
+      - name: Extract metadata (tags, labels) for Docker
+        id: meta
+        uses: docker/metadata-action@98669ae865ea3cffbcbaa878cf57c20bbf1c6c38
+        with:
+          images: my-docker-hub-namespace/my-docker-hub-repository
+
+      - name: Build and push Docker image
+        uses: docker/build-push-action@ad44023a93711e3deb337508980b4b5e9bcdc5dc
+        with:
+          context: .
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}

Dockerfile

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+FROM gradle:7.4-jdk17 as cache
+RUN mkdir -p /home/gradle/cache_home
+ENV GRADLE_USER_HOME /home/gradle/cache_home
+COPY build.gradle /home/gradle/java-code/
+WORKDIR /home/gradle/java-code
+RUN gradle clean build -i --stacktrace
+
+FROM gradle:7.4-jdk17 as builder
+COPY --from=cache /home/gradle/cache_home /home/gradle/.gradle
+COPY . /usr/src/java-code/
+WORKDIR /usr/src/java-code
+RUN gradle bootJar -i --stacktrace
+
+FROM openjdk:17
+EXPOSE 8080
+USER root
+WORKDIR /usr/src/java-app
+COPY --from=builder /usr/src/java-code/build/libs/*.jar ./app.jar
+ENTRYPOINT ["java", "-jar", "app.jar"]