chore: use alpine in Dockerfile

Dockerfile

@@ -1,9 +1,21 @@
-FROM openjdk:17-slim
+FROM eclipse-temurin:17-jre-alpine
+
+ARG USER=default
+ENV HOME /home/$USER
 
 ENV TZ=Europe/Oslo
 RUN ln -snf /usr/share/zoneinfo/$TZ /etc/localtime && echo $TZ > /etc/timezone
 
-VOLUME /tmp
-COPY /target/app.jar app.jar
+# install sudo as root
+RUN apk add --update sudo
+
+RUN adduser -D $USER \
+        && echo "$USER ALL=(ALL) NOPASSWD: ALL" > /etc/sudoers.d/$USER \
+        && chmod 0440 /etc/sudoers.d/$USER
+
+USER $USER
+WORKDIR $HOME
+
+COPY --chown=app:app /target/app.jar app.jar
 
 CMD java -jar -XX:+UseZGC $JAVA_OPTS app.jar