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

<h1>Activities</h1>

<table class="table">
  <thead>
    <tr>
      <th colspan="3"></th>
    </tr>
  </thead>

  <tbody>
    <% @activities.each do |activity| %>
      <tr>
        <td><%= link_to 'Show', group_activity_path(@group, activity) %></td>
        <td><%= link_to 'Edit', edit_group_activity_path(@group, activity) %></td>
        <td><%= link_to 'Destroy', group_activity_path(@group, activity), method: :delete, data: { confirm: 'Are you sure?' } %></td>
      </tr>
    <% end %>
  </tbody>
</table>

<br>

<%= link_to 'New Activity', new_group_activity_path(@group) %>