app/views/user_mailer/destroy_confirmation.html.erb
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
</head>
<body>
<p>Hello!</p>
<p>You have requested deleting your mooc.fi account.</p>
<p>Please proceed to the following link to continue the deletion process.</p>
<a href="<%= @url %>"><%= @url %></a>
<p>If you didn't request deleting your account, just ignore this message.</p>
</body>
</html>