Send mail using Ruby on Rails

mailer.rb

require "action_mailer"

ActionMailer::Base.delivery_method = :smtp
ActionMailer::Base.smtp_settings = {
  :address => "smtp.server.com",
  :port => 587,
  :domain => "domain.com",
  :authentication => :plain,
  :user_name => "username",
  :password => "password",
}

puts "[i] Sending messaage ..."

begin
  ActionMailer::Base.mail(
    from: "[email protected]",
    to: "[email protected]",
    subject: "test",
    body: "test"
  ).deliver
rescue Net::SMTPAuthenticationError
  puts "[-] Authentication error: Wrong credentials!"
  exit 1
end

puts "[+] E-mail has been sent!"
exit 0