create user only for ftp + vsftpd

1. sudo useradd -d /home/customuser/customdir username
2. passwd username
3. usermod -s /bin/false username
4. chown username:username filename

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pavyko su siuo tutorialu (atlikus viska is eiles)
https://www.digitalocean.com/community/tutorials/how-to-set-up-vsftpd-for-a-user-s-directory-on-ubuntu-18-04

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vsftpd.conf (veikiantis is pvz)
papildytas su: 
  allow_writeable_chroot=YES
  force_dot_files=YES

listen=NO
listen_ipv6=YES
anonymous_enable=NO
local_enable=YES
write_enable=YES
dirmessage_enable=YES
use_localtime=YES
xferlog_enable=YES
connect_from_port_20=YES
chroot_local_user=YES
user_sub_token=$USER
local_root=/home/$USER/ftp
allow_writeable_chroot=YES
force_dot_files=YES
pasv_min_port=40000
pasv_max_port=50000
userlist_enable=YES
userlist_file=/etc/vsftpd.userlist
userlist_deny=NO
secure_chroot_dir=/var/run/vsftpd/empty
pam_service_name=vsftpd
rsa_cert_file=/etc/ssl/certs/ssl-cert-snakeoil.pem
rsa_private_key_file=/etc/ssl/private/ssl-cert-snakeoil.key
ssl_enable=NO