#  emial
  config.action_mailer.delivery_method = :smtp
  config.action_mailer.smtp_settings = {
      :address              => "smtp.gmail.com",
      :port                 => 587,
      :user_name            => 'userName', #不要寫成了郵件,比如[email protected] 這個寫userName
      :password             =>  "password",
      :authentication       => 'plain',
      :enable_starttls_auto => true
  }
end
 

在App/mailer下建一個comment_mailer.rb

  default from: "userName@gmail.com"
#default from的設定一定要和你smtp的帳戶相對應，否則可能出錯。
  def comment_notify_email 

    mail to: '[email protected]', subject: 'There is a new comment on your test'
  end

class CommentsController < ApplicationController
  def create
    CommentMailer.comment_notify_email().deliver
  end
end
 

CommentMailer.comment_notify_email().deliver #一定要加上deliver