Vendor the external cookbooks

Knife-Zero doesn't include Berkshelf support, so vendoring everything in
the repo is convenient again

cookbooks/hostname/Gemfile

@@ -0,0 +1,13 @@
+source 'https://rubygems.org'
+
+gem 'berkshelf'
+gem 'chef', '~> 12.13'
+gem 'chefspec'
+gem 'foodcritic'
+gem 'rake'
+gem 'rubocop'
+
+group :integration do
+  gem 'kitchen-vagrant'
+  gem 'test-kitchen'
+end