sample how to force vagrant plugins.

enforce Vagrant-Plugins

# enforce mandatory plugins
plugins = {
	'vagrant-hostmanager' => nil,
	'vagrant-vbguest' => nil
}

plugins.each do |plugin, version|
	unless Vagrant.has_plugin? plugin
		error = "The '#{plugin}' plugin is not installed! Try running:\nvagrant plugin install #{plugin}"
		error += " --plugin-version #{version}" if version
		raise error
	end
end