Config that I'm using right now with Puma + nginx

nginx.conf

upstream puma {
  server unix://tmp/wealcash.sock fail_timeout=0;
}

server {
  listen 80 default deferred;
  server_name wealcash.com;
  root /var/www/wealcash/current/public;

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

  try_files $uri/index.html $uri @puma;
  location @puma {
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header Host $http_host;
    proxy_redirect off;
    proxy_pass http://puma;
  }

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

puma.rb

bind "unix:///tmp/wealcash.sock"
pidfile "/tmp/puma.pid"

preload_app!

min_threads = Integer(ENV['MIN_THREADS'] || 2)
max_threads = Integer(ENV['MAX_THREADS'] || 16)

threads min_threads, max_threads
workers Integer(ENV['WORKER_COUNT'] || 2)

on_worker_boot do
  ActiveSupport.on_load(:active_record) do
    config = Rails.application.config.database_configuration[Rails.env]
    config['reaping_frequency'] = ENV['DB_REAP_FREQ'] || 10 # seconds
    config['pool']              = ENV['DB_POOL'] || 5
    ActiveRecord::Base.establish_connection(config)
  end
end