Nginx configuration for SSH tunnel

upstream tunnel {
  server 127.0.0.1:3000;
}

server {
  listen 80;
  server_name dev.server.tld www.dev.server.tld;

  #optional
  location / {
    proxy_set_header  X-Real-IP  $remote_addr;
    proxy_set_header  X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header Host $http_host;
    proxy_redirect off;

    proxy_pass http://tunnel;
  }
}

ssh -vnNT -R 3000:localhost:80 root@server.tld