nginx/puma config

app.conf

# /etc/nginx/sites-available/app.conf

upstream app {
  server unix:///var/www/app/tmp/sockets/puma.sock fail_timeout=0;
}

server {
  listen 80;
  server_name localhost;

  root /var/www/app/public;

  try_files $uri/index.html $uri @app;

  location @app {
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header Host $http_host;
    proxy_redirect off;
    proxy_pass http://app;
  }

  error_page 500 502 503 504 /500.html;
  client_max_body_size 4G;
  keepalive_timeout 10;
}

puma.rb

# /var/www/app/config/puma.rb

APP_PATH = '/var/www/app'
environment ENV['RAILS_ENV'] || 'production'

daemonize true

pidfile "#{APP_PATH}/tmp/pids/puma.pid"
stdout_redirect "#{APP_PATH}/log/production.log", "#{APP_PATH}/log/production.log"

threads 0, 16

bind "unix:///#{APP_PATH}/tmp/sockets/puma.sock"

startup.txt

to start puma
$ cd /var/www/app
$ bundle exec puma