Useradd

  -b, --base-dir BASE_DIR       base directory for the home directory of the new account
  -c, --comment COMMENT         GECOS field of the new account
  -d, --home-dir HOME_DIR       home directory of the new account
  -D, --defaults                print or change default useradd configuration
  -e, --expiredate EXPIRE_DATE  expiration date of the new account
  -f, --inactive INACTIVE       password inactivity period of the new account
  -g, --gid GROUP               name or ID of the primary group of the new account
  -G, --groups GROUPS           list of supplementary groups of the new account
  -h, --help                    display this help message and exit
  -k, --skel SKEL_DIR           use this alternative skeleton directory
  -K, --key KEY=VALUE           override /etc/login.defs defaults
  -l, --no-log-init             do not add the user to the lastlog and faillog databases
  -m, --create-home             create the user's home directory
  -M, --no-create-home          do not create the user's home directory
  -N, --no-user-group           do not create a group with the same name as the user
  -o, --non-unique              allow to create users with duplicate (non-unique) UID
  -p, --password PASSWORD       encrypted password of the new account
  -r, --system                  create a system account
  -R, --root CHROOT_DIR         directory to chroot into
  -s, --shell SHELL             login shell of the new account
  -u, --uid UID                 user ID of the new account
  -U, --user-group              create a group with the same name as the user
  -Z, --selinux-user SEUSER     use a specific SEUSER for the SELinux user mapping

## -U, --user-group              사용자명과 동일한 그룹을 생성한다.
## -m, --create-home             사용자 홈 디렉토리를 생성한다.
## -s /bin/bash                  로그인할 기본 쉘을 지정한다. (이게 없으면 자동완성이 안된다)
sudo useradd -s /bin/bash -U -m -p [PASSWORD] [USERNAME]

sudo gpasswd -a [USERNAME] wheel

$ su -l [USERNAME]

echo "[USERNAME] ALL=(ALL) NOPASSWD:ALL" > /etc/sudoers.d/[USERNAME]
chmod 440 /etc/sudoers.d/[USERNAME]

# sudo usermod -aG sudo [USERNAME]

userdel -r vagrant

$ groupadd docker
$ useradd -G docker [USERNAME]