groups: Add the enterprise user to useful groups

In Debian stretch by default, a user with no groups is barey a user at all. We
need to add enterprise to a whole list of groups to make the user userful.

Change-Id: I06756d5f5ef302ebaf3232caafab1738b4352c57
diff --git a/rootfs.mk b/rootfs.mk
index 87aa383..e871c50 100644
--- a/rootfs.mk
+++ b/rootfs.mk
@@ -10,6 +10,19 @@
 ROOTFS_DIR := $(PRODUCT_OUT)/obj/ROOTFS/rootfs
 ROOTFS_RAW_IMG := $(PRODUCT_OUT)/obj/ROOTFS/rootfs.raw.img
 
+USER_GROUPS := \
+	adm \
+	audio \
+	bluetooth \
+	disk \
+	games \
+	input \
+	plugdev \
+	staff \
+	sudo \
+	users \
+	video
+
 rootfs: $(PRODUCT_OUT)/rootfs.img
 
 gpu:
@@ -29,6 +42,9 @@
 	echo "127.0.0.1 enterprise" | sudo tee -a $(ROOTFS_DIR)/etc/hosts
 	sudo chroot $(ROOTFS_DIR) mkdir -p /home/enterprise
 	sudo chroot $(ROOTFS_DIR) adduser enterprise --home /home/enterprise --shell /bin/bash --disabled-password --gecos ""
+	for group in $(USER_GROUPS); do \
+		sudo chroot $(ROOTFS_DIR) adduser enterprise $$group; \
+	done
 	sudo chroot $(ROOTFS_DIR) chown enterprise:enterprise /home/enterprise
 	sudo chroot $(ROOTFS_DIR) bash -c "echo 'enterprise:enterprise' | chpasswd"
 	echo "nameserver 8.8.8.8" | sudo tee $(ROOTFS_DIR)/etc/resolv.conf