Why is my Sinatra app showing a blank screen?
===

My Sinatra app was working on my local server a few days ago, but now it simply isn't running, and all I get is a blank screen. Even when I deploy to Heroku, nothing works. 

Here's a GitHub repository where you can check out my code: [https://github.com/aayalur/Sinfoursq][1]


  [1]: https://github.com/aayalur/Sinfoursq

I think the problem is with my `config.ru` file.

    # Gemfile
    #require "rubygems"
    #require "bundler/setup"
    #require "sinatra"
    
    require "./main"
     
    set :run, false
    set :raise_errors, true
     
    run Sinatra::Application

Thanks!