aardbei/app/views/activities/index.html.h...

%h1
  - if params[:past]
    = t 'activities.past'
  - else
    = t 'activities.upcoming'

- isleader = @group.leaders.include?(current_person) || current_person.is_admin?
.btn-group.pull-right
  - if params[:past]
    = link_to group_activities_path(@group), class: 'btn btn-default' do
      %i.fas.fa-history
      = t 'activities.upcoming'
  - else
    = link_to group_activities_path(@group, past: true), class: 'btn btn-default' do
      %i.fas.fa-history
      = t 'activities.past'
  - if isleader
    = link_to new_group_activity_path(@group), class: 'btn btn-default' do
      %i.fas.fa-plus
      = t 'activities.new'

%table.table
  %thead
    %tr
      %th
        = t 'activerecord.attributes.activity.name'

      %th
        = t 'activerecord.attributes.activity.start'

      %th
        P/A/?

      - if isleader
        %th

  %tbody
    - @activities.each do |a|
      %tr
        %td
          = link_to a.name, group_activity_path(@group, a)

        %td
          = l a.start, format: :short

        %td
          = a.human_state_counts

        - if isleader
          %td
            = link_to edit_group_activity_path(@group, a) do
              %i.fas.fa-pencil-alt

= will_paginate @activities