def vendor(name)
        directory = plugin_dir(name)
        return true if directory.exist?
        directory.mkpath
        Dir.chdir(directory) do |dir|
          run("curl #{vendor_url}/#{name}.tgz -s --fail --retry 3 --retry-connrefused --connect-timeout #{curl_connect_timeout_in_seconds} -o - | tar xzf -")
        end
      end
vendors an individual plugin
@param [String] name of the plugin