Sinatra configuring environments on the fly

Question

I have successfull written a little Sinatra application and already successfully deployed it on heroku.

However I want to run that application in development mode on

Answer 1

Look at the Heroku documentation:

http://devcenter.heroku.com/articles/rack#frameworks

That's basically what I use for my app, when I start it locally it runs on port 4567.