action_mailer_for_sinatra.rb

# Configure ActionMailer
require 'action_mailer'
ActionMailer::Base.template_root = "#{File.dirname(__FILE__)}/views"
ActionMailer::Base.smtp_settings = {
  :address        => "smtp.sendgrid.net",
  :port           => "25",
  :authentication => :plain,
  :user_name      => "username@domain.com",
  :password       => "yourpassword"
}

# Make sure we don't accidentally send emails in development
configure :development do
  ActionMailer::Base.raise_delivery_errors = false
  ActionMailer::Base.delivery_method = :test
  ActionMailer::Base.logger = Logger.new(STDOUT)
end