Guard::Hydra to use Hydra for run_all

Guardfile.rb

require 'guard'
require 'guard/guard'
require 'guard/rspec'

module ::Guard
  class ::Guard::Hydra < ::Guard::RSpec
    def start
      UI.info "Guard::Hydra is giving Guard::RSpec super run_all powers. Whoa!"
      super
    end

    def run_all
      system %{rake RAILS_ENV=test hydra:spec}
    end
  end
end