fix group offer missing as dependent action from volunteer

app/models/volunteer.rb

@@ -48,7 +48,7 @@ class Volunteer < ApplicationRecord
 
   has_many :billing_expenses
 
-  has_many :group_assignments
+  has_many :group_assignments, dependent: :delete_all
   has_many :group_assignment_logs
 
   has_many :group_offers, through: :group_assignments

app/views/group_offers/_group_assignments_index.html.slim

@@ -12,7 +12,7 @@
       - group_assignments.each do |group_assignment|
         tr
           td
-            = link_to_if(policy(Volunteer).show?, group_assignment.volunteer.contact.full_name, volunteer_path(group_assignment.volunteer))
+            = link_to_if(policy(group_assignment.volunteer).show?, group_assignment.volunteer.contact.full_name, volunteer_path(group_assignment.volunteer))
           - if params[:format] == 'pdf'
             td= group_assignment.volunteer.contact.primary_email
           td= group_assignment.responsible ? t_attr(:responsible, GroupAssignment) : t_attr(:member, GroupAssignment)

test/system/group_offers_test.rb

@@ -140,12 +140,14 @@ class GroupOffersTest < ApplicationSystemTestCase
     assert page.has_text? title
   end
 
-  test 'deleting volunteer does not crash group offer show' do
+  test 'deleting_volunteer_does_not_crash_group_offer_show' do
     login_as create(:user)
     volunteer1 = create :volunteer
     volunteer2 = create :volunteer
-    group_offer = create :group_offer, volunteers: [volunteer1, volunteer2]
-
+    group_offer = create :group_offer
+    [volunteer1, volunteer2].map do |volunteer|
+      create(:group_assignment, volunteer: volunteer, group_offer: group_offer)
+    end
     visit group_offer_path(group_offer)
     assert page.has_link? volunteer1.contact.full_name
     assert page.has_link? volunteer2.contact.full_name
@@ -153,8 +155,8 @@ class GroupOffersTest < ApplicationSystemTestCase
     Volunteer.find(volunteer1.id).destroy
 
     visit group_offer_path(group_offer)
-    refute page.has_link? volunteer1.contact.full_name
     assert page.has_link? volunteer2.contact.full_name
+    refute page.has_link? volunteer1.contact.full_name
   end
 
   test 'department_manager_has_group_assignment_select_dropdowns_in_edit_form_filled' do