Prepare to build. You need to install GraalVM, native-image tool and set the environment variables GRAALVM_HOME. More detail is in this link.
https://quarkus.io/guides/building-native-image-guide

To build Native image for docker.
./gradlew buildNative --docker-build=true

docker build
docker build -f Dockerfile -t sample/quarkus-app .

docker run
docker run -i --rm -p 8080:8080 sample/quarkus-app