Add checkbox for member event webhook

First step to adding UI

app/views/shared/web_hooks/_form.html.haml

@@ -48,6 +48,12 @@
         %strong= s_('Webhooks|Confidential Issues events')
       %p.text-muted.ml-1
         = s_('Webhooks|This URL will be triggered when a confidential issue is created/updated/merged')
+    %li
+      = form.check_box :member_events, class: 'form-check-input'
+      = form.label :member_events, class: 'list-label form-check-label ml-1' do
+        %strong= s_('Webhooks|Member events')
+      %p.text-muted.ml-1
+        = s_('Webhooks|This URL will be triggered when a member is added to a group')
     %li
       = form.check_box :merge_requests_events, class: 'form-check-input'
       = form.label :merge_requests_events, class: 'list-label form-check-label ml-1' do

ee/spec/controllers/groups/hooks_controller_spec.rb

@@ -39,7 +39,8 @@ RSpec.describe Groups::HooksController do
           token: 'TEST TOKEN',
           url: 'http://example.com',
           wiki_page_events: true,
-          deployment_events: true
+          deployment_events: true,
+          member_events: true
         }
 
         post :create, params: { group_id: group.to_param, hook: hook_params }
@@ -81,7 +82,8 @@ RSpec.describe Groups::HooksController do
             url: 'http://example.com',
             wiki_page_events: true,
             deployment_events: true,
-            releases_events: true
+            releases_events: true,
+            member_events: true
           }
         end
 

locale/gitlab.pot

@@ -30881,6 +30881,9 @@ msgstr ""
 msgid "Webhooks|Job events"
 msgstr ""
 
+msgid "Webhooks|Member events"
+msgstr ""
+
 msgid "Webhooks|Merge request events"
 msgstr ""
 
@@ -30917,6 +30920,9 @@ msgstr ""
 msgid "Webhooks|This URL will be triggered when a confidential issue is created/updated/merged"
 msgstr ""
 
+msgid "Webhooks|This URL will be triggered when a member is added to a group"
+msgstr ""
+
 msgid "Webhooks|This URL will be triggered when a merge request is created/updated/merged"
 msgstr ""