vagrant_stub.rb

if CONF.has_key?("mounts")
    CONF['mounts'].each do |folder|
        config.vm.share_folder(folder['name'], folder['virtual'], folder['host'], :nfs => true)
    end
end

vagrantconfig_local.yaml

nfs: true

mounts:
    - name: "code"
      virtual: "/var/code"
      host: "~/Code"

Vagrantfile.rb

require "yaml"

# Load up our vagrant config files -- vagrantconfig.yaml first
_config = YAML.load(File.open(File.join(File.dirname(__FILE__),
                    "vagrantconfig.yaml"), File::RDONLY).read)

# Local-specific/not-git-managed config -- vagrantconfig_local.yaml
begin
    _config.merge!(YAML.load(File.open(File.join(File.dirname(__FILE__),
                   "vagrantconfig_local.yaml"), File::RDONLY).read))
rescue Errno::ENOENT # No vagrantconfig_local.yaml found -- that's OK; just
                     # use the defaults.
end

CONF = _config
MOUNT_POINT = '/var/apps/myapp/source'

Vagrant::Config.run do |config|

    # Box set up stuff removed

    if CONF['nfs'] == false or RUBY_PLATFORM =~ /mswin(32|64)/
        nfs = false
    end

    config.vm.share_folder("app_root", MOUNT_POINT, ".", :nfs => nfs)

    if CONF.has_key?("mounts")
        CONF['mounts'].each do |folder|
            config.vm.share_folder(folder['name'], folder['virtual'], folder['host'], :nfs => true)
        end
    end

    # Provisioning removed

end