How to configure Sinatra classic to use Puma

Question

I have an old project with classic Sinatra (not modular < Sinatra::Base). How can I make it use the Puma web server instead of Thin?

The only examples on the internet I could find using Puma were with modular Sinatra.

reference: http://www.sinatrarb.com/intro.html#Modular%20vs.%20Classic%20Style

Answer 1

Or if you just want use rakeup you can add to your config.ru

#\ -s puma
require './yourapp'
run Sinatra::Application

Answer 2

Just create config.ru:

require './yourapp'
run Sinatra::Application

then run:

puma