diff --git a/install.sh b/install.sh
index 516952d..82bbacc 100644
--- a/install.sh
+++ b/install.sh
@@ -4,7 +4,7 @@ set -e
 
 # on fresh install remove cdrom-repo and install sudo if not available
 which sudo >/dev/null 2>&1 || su -c "sed -i '/cdrom/d' /etc/apt/sources.list ; apt update ; apt -y install sudo"
-id | grep -q '(sudo)' || su -c "/usr/sbin/usermod -a sudo ${USER}"
+id | grep -q '(sudo)' || su -c "/usr/sbin/usermod -a -G sudo ${USER}"
 
 sudo apt-get -y install python3-pip git
 sudo pip install ansible