membersystem/src/membership/templates/membership/membership_admin.html

{% extends "base.html" %}
{% load i18n %}

{% block content %}

    {% for period in subscription_periods %}
        <h3>{{ period }}</h3>
        {% for membership in period.membership_set.all %}
            <p>{{ membership.user.username }}</p>
        {% endfor %}
    {% endfor %}

{% endblock %}