My nginx config file using puma for rails app

my_app.conf

upstream app {
  server unix:///path/to/rails/puma.sock fail_timeout=0;
}

server {
  server_name 1.2.3.4 www.myrailsapp.com;
  root /path/to/rails/public;

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

  location / {
    proxy_pass http://app;
    proxy_set_header Host $host;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header X-Forwarded-Host 'www.railsapp.com';
    proxy_set_header X-Forwarded-Proto $scheme;
  }

  location ~ ^/(500|404|422).html {
    root /path/to/rails/public;
  }

  error_page 500 502 503 504 /500.html;
  error_page 404 /404.html;
  error_page 422 /422.html;

  client_max_body_size 4G;
  keepalive_timeout 10;
}