nginx domain and subdomain reverse proxy

nginx.conf

worker_processes  2;

events {
    worker_connections  1024;
}

http {
    include            mime.types;
    default_type       application/octet-stream;
    sendfile           on;
    keepalive_timeout  65;

    server {
        listen       80;
        server_name  mysuperapp.com;

        location / {
            proxy_pass http://localhost:9000;
            proxy_http_version 1.1;
            proxy_set_header Upgrade $http_upgrade;
            proxy_set_header Connection 'upgrade';
            proxy_set_header Host $host;
            proxy_cache_bypass $http_upgrade;
        }

        error_page   500 502 503 504  /50x.html;
        location = /50x.html {
            root   html;
        }
    }

    server {
        listen       80;
        server_name  app.mysuperapp.com;

        location / {
            proxy_pass http://localhost:9001;
            proxy_http_version 1.1;
            proxy_set_header Upgrade $http_upgrade;
            proxy_set_header Connection 'upgrade';
            proxy_set_header Host $host;
            proxy_cache_bypass $http_upgrade;
        }

        error_page  500 502 503 504  /50x.html;
        location = /50x.html {
            root   html;
        }
    }
}