transmission_ynh/conf/nginx.conf

location PATHTOCHANGE/transmission {
    proxy_pass http://127.0.0.1:9091PATHTOCHANGE/transmission;
}
location PATHTOCHANGE {
    proxy_pass http://127.0.0.1:9091/;
}
location PATHTOCHANGE/downloads {
    alias /home/yunohost.transmission/completed/;
    autoindex on;
}