                              
                                    <!-- Calculate contributors -->
                                    {% if expense.user_id in months[month].by_user %}
                                        {% set _ = months[month].by_user.update({expense.user_id: months[month].by_user[expense.user_id] + expense.amount}) %}
                                    {% else %}
                                        {% set _ = months[month].by_user.update({expense.user_id: expense.amount}) %}
   