useradd: user 'root' already exists
Created by: Wrench666
Hi, I have a problem for installation.
---> Running in 1f75f515af71
#useradd: user 'root' already exists
#The command '/bin/sh -c useradd --uid=$DOCKER_UID --gid=$DOCKER_GID -m --groups wheel $DOCKER_USER' returned a non-zero code: 9
#make: *** [Makefile:29: build-forem-selfhost] Error 9
#root@teknopad:~/forem-selfhost-docker#
How to fix this error?