Sinatra + Passenger + Nginx

app.rb

require 'sinatra'

get '/' do
  'Hello Sinatra!'
end

config.ru

require 'rubygems'
Gem.clear_paths

require './app'

run Sinatra::Application

Nginx.conf

# Nginx conf, for example in /etc/nginx/sites-available/myapp.com

server {
    listen 80;
    server_name myapp.com;
    passenger_enabled on;
    passenger_app_env production;
    root /var/www/myapp.com/public;
    passenger_ruby /usr/local/rvm/gems/ruby-2.7.1/wrappers/ruby;
    location / {
        try_files $uri @app;
    }

    location @app {
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header Host $host;
        proxy_redirect off;
    }

    error_log /var/log/nginx/myapp.com_error.log;
    access_log /var/log/nginx/myapp.com_access.log;
}