fix backend docker image

[jonasfroeller]

quarkus dockerfile error: docker: Error response from daemon: failed to create task for container: failed to create shim task: OCI runtime create failed: runc create failed: unable to start container process: exec: "./application": permission denied: unknown.

custom dockerfile error: docker: Error response from daemon: failed to create task for container: failed to create shim task: OCI runtime create failed: runc create failed: unable to start container process: exec: "./creative-mind-backend-1.0-SNAPSHOT-runner": permission denied: unknown.

aberger:

#!/usr/bin/env bash

set -e

rm -rf target
mvn -B clean package
mkdir -p target/deploy
cp target/*-runner.jar target/deploy/
docker build --tag backend --file ./src/main/docker/Dockerfile ./target/deploy