Handle the group not being GID=1000.

@@ -6,7 +6,7 @@ tool_uid="$(id -u tool)"
 tool_gid="$(id -g tool)"
 
 adjust_tool_uid_gid() {
-	declare usermod_args=()
+	declare usermod_args=() groupmod_args=()
 	declare -a new_groups=()
 
 	if [[ $MAP_UID ]]; then
@@ -14,7 +14,9 @@ adjust_tool_uid_gid() {
 	fi
 	if [[ $MAP_GROUPS ]]; then
 		set -- $MAP_GROUPS
-		[[ $(id -g tool) -ne $1 ]] && usermod_args+=(-g $1)
+		if [[ $tool_gid -ne $1 ]]; then
+			groupmod_args=(-g "$1")
+		fi
 		shift
 		for group in "$@"; do
 			groupadd -g $group -o tool_$group
@@ -25,6 +27,9 @@ adjust_tool_uid_gid() {
 			usermod_args+=(-aG "${new_groups[*]}")
 		fi
 	fi
+	if [[ ${#groupmod_args[*]} -gt 0 ]]; then
+		groupmod "${groupmod_args[@]}" tool
+	fi
 	if [[ ${#usermod_args[*]} -gt 0 ]]; then
 		usermod "${usermod_args[@]}" tool
 	fi