Users may delete all tasks of a group, i.e. delete the whole group.

app/controllers/periodic_task_groups_controller.rb

@@ -0,0 +1,8 @@
+class PeriodicTaskGroupsController < ApplicationController
+  def destroy
+    @task_group = PeriodicTaskGroup.find(params[:id])
+    @task_group.destroy
+
+    redirect_to tasks_url, notice: I18n.t('periodic_task_groups.destroy.notice')
+  end
+end

app/helpers/periodic_task_groups_helper.rb

@@ -0,0 +1,2 @@
+module PeriodicTaskGroupsHelper
+end

app/views/tasks/show.haml

@@ -29,3 +29,6 @@
   = link_to t('ui.edit'), edit_task_path(@task), class: 'btn'
   = link_to t('ui.delete'), task_path(@task), :method => :delete, :confirm => "Die Aufgabe wirklich löschen?",
     class: 'btn btn-danger'
+  - if @task.periodic
+    = link_to t('ui.delete_all'), periodic_task_group_path(@task.periodic_task_group), :method => :delete, 
+      :confirm => "Alle Aufgaben dieser wöchentlichen Aufgabe wirklich löschen?", class: 'btn btn-danger'