How can i send email with ruby on rails 3.1 ?

I have installed sendmail .

I have read this =>

I need to do =>

rails generate mailer UserMailer

app/mailers/user_mailer.rb =>

class UserMailer < ActionMailer::Base
  default :from => ""

  def welcome_email(user)
    @user = user
    @url = ""
    mail(:to =>, :subject => "Welcome to My Awesome Site")

What will be the email address of :from => .. ?

I need to send email to, and in any domain like

How can i do this ?

It will be helpful if someone can reply with explaination ?

Form: ist whatever email you want it to be… the from field is the senders address. So it could be you address or or similar. But it would be good advise if you ensure ownership over the used domain or at least the used email address.