Bundle assets when they change.

jammit-pre-commit.rb

#!/usr/bin/env ruby

require 'yaml'

top_dir = `git rev-parse --show-toplevel`.chomp
changes = `git diff --cached --name-only`.chomp.split

assets = YAML.load_file "#{top_dir}/config/assets.yml"
assets = assets['javascripts'].values + assets['stylesheets'].values
assets.flatten!

unless (assets & changes).empty?
  p "Compressing assets with jammit... "
  `bundle exec jammit --force`
  puts "done!"
  `git add #{top_dir}/public/assets`
end