Delete hash.rb

This is on account of two things:

1) a bug I saw when the app gets preloaded and I try to request anything with an integer that uses `#to_query`.

For example, `url_for(test: 1)` will throw an exception "undefined method `gsub' for 1:Fixnum"

2) As we know, monkey-patches are bad practice. If we really want to use an alternate `#to_query`  method, we should create a utility class instead. But since Rails 3 implements `#to_query` already, we should remove this file altogether.