byebug as debugger monkey patch

byebug_as_debugger.rb

module Rails
  module Rack
    class Debugger
      def initialize(app)
        @app = app

        # clear ARGV so that rails server options aren't passed to IRB
        ARGV.clear

        require 'byebug'

        ::Byebug.start
        puts "=> Byebug enabled"
      rescue LoadError
        puts "You're missing the 'byebug' gem. Add it to your Gemfile, bundle " \
               "it and try again."
        exit(1)
      end

      def call(env)
        @app.call(env)
      end
    end
  end
end

ref: deivid-rodriguez/byebug#2