Sprockets::Glob

adds require_glob and stub_glob directives to sprockets

These were already in an example in the Sprockets repo, but we've used them enough to package them into a gem.

gem 'sprockets-glob'

First you need to register the Sprockets::Glob::DirectiveProcessor with the correct MIME types. Then you can use it in your normal Sprockets pipeline. Here's an example using javascript:

# config/initializers/sprockets.rb
require 'sprockets/glob'
Rails.application.assets.register_processor('application/javascript', Sprockets::Glob::DirectiveProcessor)

# application.js
//= require_glob features/**/*.js
//= stub_glob features/**/*test.js