Update Nginx config in the wiki

[NTag]

The current one didn't worked for me, the /sync endpoint wasn't responding and the page was displaying "Connecting…".

This one worked:

location / {
    proxy_pass http://127.0.0.1:3000/;

    location /sync {
        proxy_pass http://127.0.0.1:3000/sync;
        proxy_set_header Connection '';
        proxy_http_version 1.1;
        chunked_transfer_encoding off;
        proxy_buffering off;
        proxy_cache off;
    }
}