post_install() {

    if ! getent group matemat >/dev/null; then
        groupadd --system matemat
    fi

    if ! getent passwd matemat >/dev/null; then
        useradd --system --create-home --gid matemat --home-dir /var/lib/matemat --shell /usr/bin/nologin matemat
    fi

    chown matemat:matemat /var/lib/matemat
    chmod 0750 /var/lib/matemat
    ln -sf /var/lib/matemat/upload /usr/lib/matemat/static/upload

    systemctl daemon-reload

}

pre_remove() {

    systemctl stop matemat.service
    userdel matemat

}

post_remove() {

    systemctl daemon-reload

}