submodule_strategy.rb

# Usage: 
# 1. Drop this file into lib/capistrano/submodule_strategy.rb
# 2. Add the following to your Capfile:
#   require './lib/capistrano/submodule_strategy'
# 3. Add the following to your config/deploy.rb
#   set :git_strategy, SubmoduleStrategy

require 'capistrano/git'

module SubmoduleStrategy
  # do all the things a normal capistrano git session would do
  include Capistrano::Git::DefaultStrategy

  def test
    test! " [ -d #{repo_path}/.git ] "
  end

  def check
    test! :git, :'ls-remote', repo_url
  end

  def clone
    git :clone, '-b', fetch(:branch), '--recursive', repo_url, repo_path
  end

  def update
    git :remote, :update
  end

  # put the working tree in a release-branch,
  # make sure the submodules are up-to-date
  # and copy everything to the release path
  def release
    git :checkout, fetch(:branch)
    git :submodule, :update, '--init', '--recursive'
    context.execute "rsync -ar --exclude=.git\* #{repo_path}/ #{release_path}"
  end
end