location = /bookstack { 
        return 301 https://$host/bookstack/;
}

location /bookstack/ {
    proxy_pass         http://127.0.0.1:6875/;
    proxy_redirect     off;
    proxy_set_header   Host $host;
    proxy_set_header   X-Real-IP $remote_addr;
    proxy_set_header   X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header   X-Forwarded-Host $server_name;
}