devise

https://github.com/plataformatec/devise

Ruby

Flexible authentication solution for Rails with Warden.

Mail.deliver

Send an email using the default configuration.  You do need to set a default
configuration first before you use self.deliver, if you don't, an appropriate
error will be raised telling you to.

If you do not specify a delivery type, SMTP will be used.

 Mail.deliver do
  to '[email protected]'
  from '[email protected]'
  subject 'This is a test email'
  body 'Not much to say here'
 end

You can also do:

 mail = Mail.read('email.eml')
 mail.deliver!

And your email object will be created and sent.

Source | Google | Stack overflow

Edit

git clone [email protected]:plataformatec/devise.git
cd devise
open

Contribute

# Make a new branch

git checkout -b -your-name--update-docs-Mail-deliver-for-pr

# Commit to git

git add git commit -m "better docs for Mail.deliver"

# Open pull request

gem install hub # on a mac you can `brew install hub`

hub fork

git push <your name> -your-name--update-docs-Mail-deliver-for-pr

hub pull-request

# Celebrate!