SMTP over SSL + GMailでメールを送信したい

recepi_112.rb

require 'net/smtp'
require 'rubygems'
require 'tmail'
require 'kconv'
require 'tlsmail'

smtp_server = 'smtp.gmail.com'
smtp_port   = 587
from_addr   = 'gmail_user@gmail.com'
to_addrs    = ['da@re.ka', 'do@nata.ka']

user        = 'gmail_user'
pass        = 'gmail_pass'

mail                  = TMail::Mail.new
mail.to               = to_addrs
mail.from             = from_addr
mail.subject          = "メールのテストです".tojis
mail.date             = Time.now
mail.mime_version     = '1.0'
mail.set_content_type 'text', 'plain', {'charset' => 'iso-2022-jp'}
mail.body             = "RubyでGMailを使ってメールを送信する\nRuby逆引きレシピAdvent Calendar\n13日目のサンプル".tojis

ssl_smtp = Net::SMTP.new(smtp_server, smtp_port)
ssl_smtp.enable_tls(OpenSSL::SSL::VERIFY_NONE)
ssl_smtp.start('localhost', user, pass, :plain) do |smtp|
  smtp.send_mail(mail.to_s, from_addr, *to_addrs)
end