diff --git a/docker-contributor/scripts/start.sh b/docker-contributor/scripts/start.sh
index bf583e15..06e27f5b 100644
--- a/docker-contributor/scripts/start.sh
+++ b/docker-contributor/scripts/start.sh
@@ -10,8 +10,8 @@ function file_or_env {
 }
 
 echo "[..] Changing user/group ID"
-groupmod -g "${GID}" domjudge
-usermod -u "${UID}" domjudge
+sudo groupmod -g "${GID}" domjudge
+sudo usermod -u "${UID}" domjudge
 echo "[ok] User ID set to ${UID} and group ID set to ${GID}"; echo
 
 echo "[..] Setting timezone"