first implementation

backend/Dockerfile

@@ -0,0 +1,13 @@
+# ---- Build stage ----
+FROM eclipse-temurin:21-jdk-alpine AS build
+WORKDIR /app
+COPY pom.xml .
+COPY src ./src
+RUN apk add --no-cache maven && mvn -q -DskipTests package
+
+# ---- Runtime stage ----
+FROM eclipse-temurin:21-jre-alpine
+WORKDIR /app
+COPY --from=build /app/target/*.jar app.jar
+EXPOSE 8080
+ENTRYPOINT ["java", "-jar", "app.jar"]