Fix user and entrypoint stuff

docker-entrypoint.sh

@@ -1,5 +1,5 @@
-#!/bin/sh
-set -e
+#!/bin/bash
+set -euxo pipefail
 
 DOCKER_USER='dockeruser'
 DOCKER_GROUP='dockergroup'
@@ -12,7 +12,7 @@ if ! id "$DOCKER_USER" >/dev/null 2>&1; then
     echo "Starting with $USER_ID:$GROUP_ID (UID:GID)"
 
     addgroup --gid $GROUP_ID $DOCKER_GROUP
-    adduser -s /bin/sh -u $USER_ID -G $DOCKER_GROUP -D $DOCKER_USER
+    adduser --shell /bin/sh --uid $USER_ID --gid $GROUP_ID $DOCKER_USER
 
     chown -vR $USER_ID:$GROUP_ID /opt/minecraft
     chmod -vR ug+rwx /opt/minecraft