again the part between "!!!" and "%body" (inclusive) should be in a layout, think about it that it will later contain the mitnadvim header and logo (which will remain the same for all mails), and it will contain the footer and maybe even an un-subscribe link which again will remain the same for all mails, we don't want to duplicate this content between all the email templates.

You can place the mail layout under app/views/layouts/mail.html.haml

http://guides.rubyonrails.org/action_mailer_basics.html#action-mailer-layouts