Sinatra logging & stack traces

I am currently running an application that I am developing on Apache / Passenger. When I used a shotgun, I was able to view a stack of stacks.

I am trying to set up registration using Sinatra and really damn time. I have my config.ru:

require 'sinatra'
require 'rubygems'

root = ::File.dirname(__FILE__)
require ::File.join( root, 'application' )

set :environment, :development
set :root,  root
set :app_file, File.join(root, 'application.rb')
disable :run

configure :development do
  enable :logging, :dump_errors, :raise_errors
end
set :show_exceptions, true if development?

run Application.new

app.rb:

class App < Sinatra::Base
    logger = ::File.open("log/development.log", "a+")
    STDOUT.reopen(logger)
    STDERR.reopen(logger)

    Application.use Rack::CommonLogger, logger
end

Currently I can get general journals, but I don't need general journals. I need to be able to see either in the web browser, or in the log, on the server (500) that I get. Any help is appreciated!