init command should default to Berkshelf

[jtimberman]

The Vagrantfile rendered by the init command should set up Berkshelf support by default. This means:

• Add gem "berkshelf" to Gemfile
• Add require 'berkshelf/vagrant' to Vagrantfile
• Generate a default Berksfile:

source :opscode
metadata

group :test do
  cookbook "apt"
  cookbook "yum"
  cookbook "minitest-handler"

  require 'pathname'
  cb_dir = ::File.join('.', 'test', 'kitchen', 'cookbooks')
  if ::File.exist?(cb_dir)
    Pathname.new(cb_dir).children.select(&:directory?).each do |c|
      cookbook c.basename.to_s, :path => ::File.join(cb_dir, c.basename.to_s).to_s
    end
  end
end

The last part is to support #24.

A command-line option could be added to disable Berkshelf support, or switch to librarian-chef.

[jtimberman]

We don't need the Gemfile/Vagrantfile integration. A "--create-berksfile" for Berkshelf would still be nice.

[jtimberman]

This is resolved with existing auto-detection magic.