{% set days = age.days %}
{% set registration_url = request.route_url('user.register') %}
<strong>You've been invited to join Workout With Friends!</strong>
<p>
    {{ user.fullname if user else 'We' }} would like to invite you to join Workout
    With Friends! Please visit the link belo to sign up for a free account.
</p>
<a href="{{ registration_url }}">{{ registration_url }}</a>