Comentar as linhas para explicar a configuração

nginx.conf

upstream web {
  server localhost:3000;
}

server {
  listen 80;
  server_name 104.236.254.113;
  
  root /home/taskv/app/current/public;
  index index.html index.htm;
  
  client_max_body_size 10M;
  
  location ~ (\.(php|aspx|asp)|myadmin) {
    return 444;
  }

  location ~ ^/assets/ {
    gzip_static on;
    expires max;
    add_header Cache-Control public;
    access_log off;
  }

  location / {
    try_files $uri @app;
  }
  location @app {
    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_set_header X-FORWARDED_PROTO $scheme;
    proxy_redirect off;
    proxy_pass http://web;
    break;
  }

  error_page 500 502 503 504 /500.html;
  location = /500.html {
    root /home/taskv/app/current/public;
  }
}