Hardcode uid, gid in Dockerfile

Dockerfile

@@ -1,12 +1,15 @@
 FROM docker.io/eclipse-temurin:21
 
+ARG USER_ID=10001
+ARG GROUP_ID=10001
+
 RUN apt-get update \
     && apt-get install -y ffmpeg \
     && apt-get clean \
     && rm -rf /var/lib/apt/lists/*
 
-RUN groupadd --system app \
-    && useradd --no-log-init --system --shell /sbin/nologin --gid app app
+RUN groupadd -g ${GROUP_ID} app \
+    && useradd --no-log-init -u ${USER_ID} -g app --shell /sbin/nologin app
 
 WORKDIR /app
 
@@ -14,7 +17,7 @@ ARG JAR_FILE=build/libs/*.jar
 COPY --chown=app:app ${JAR_FILE} app.jar
 COPY --chown=app:app build/resources/main/static BOOT-INF/classes/static
 
-USER app:app
+USER ${USER_ID}:${GROUP_ID}
 
 ENTRYPOINT ["java","-jar","app.jar"]