Nginx, Sinatra, and Puma.

app.rb

#!/usr/bin/env ruby

require 'sinatra'

configure {
  set :server, :puma
}

class Pumatra < Sinatra::Base
  get '/' do
    return 'It works!'
  end

  run! if app_file == $0
end

commands.sh

bundle install --path vendor/bundle

mkdir -p tmp/puma

bundle exec puma --config config/puma.rb

config.ru

#!/usr/bin/env ruby

require './app'

run Pumatra

Gemfile

source :rubygems
gem "puma"
gem "sinatra"

nginx.conf

upstream app {
  server unix:///appdir/tmp/puma/socket;
}

server {
  listen 80;
  server_name app.com;

  root /appdir/public;
  access_log /appdir/log/nginx.access.log;
  error_log /appdir/log/nginx.error.log info;

  location / {
    try_files $uri @puma;
  }

  location @puma {
    include proxy_params;

    proxy_pass http://app;
  }
}

puma.rb

root = "#{Dir.getwd}"

bind "unix://#{root}/tmp/puma/socket"
pidfile "#{root}/tmp/puma/pid"
state_path "#{root}/tmp/puma/state"
rackup "#{root}/config.ru"

threads 4, 8

activate_control_app

If you are getting an error at the line include proxy_params; you may want to see this.