Sinatra reload source file changes in development mode

Sinatra Reloader is a sinatra extension which reloads source files while in development mode, this functionality was removed from base sinatra in 0.9.2

gem install sinatra-reloader

In your app (classy style)

require "sinatra/base"
require "sinatra/reloader"

class Foo < Sinatra::Base
  configure(:development) do
    register Sinatra::Reloader
    also_reload "models/*.rb"
    also_reload "helpers/*.rb"
    #dont_reload "lib/**/*.rb"
  end
end

Source