add back Dockerfile as example

Dockerfile

@@ -0,0 +1,15 @@
+FROM maven:3.5-jdk-11-slim as build
+
+# Resolve all the dependencies and cache them to save a LOT of time
+COPY pom.xml /usr/src/myapp/
+RUN mvn -f /usr/src/myapp/pom.xml dependency:resolve dependency:resolve-plugins
+
+# Build the application, usually only this part gets rebuilt locally, use offline mode and skip tests
+COPY src /usr/src/myapp/src
+RUN mvn -f /usr/src/myapp/pom.xml clean package -DskipTests -o
+
+# The final image should have minimal layers
+FROM openjdk:11-jre-slim
+RUN apt-get update && apt-get install curl -y
+COPY --from=build /usr/src/myapp/target/app.jar app.jar
+ENTRYPOINT java -jar app.jar