Include the username in user_create/destroy system hooks.

app/services/system_hooks_service.rb

@@ -47,7 +47,8 @@ class SystemHooksService
       data.merge!({
         name: model.name,
         email: model.email,
-        user_id: model.id
+        user_id: model.id,
+        username: model.username
       })
     when ProjectMember
       data.merge!(project_member_data(model))

doc/system_hooks/system_hooks.md

@@ -129,6 +129,7 @@ X-Gitlab-Event: System Hook
         "email": "js@gitlabhq.com",
    "event_name": "user_create",
          "name": "John Smith",
+     "username": "js",
       "user_id": 41
 }
 ```
@@ -142,6 +143,7 @@ X-Gitlab-Event: System Hook
         "email": "js@gitlabhq.com",
    "event_name": "user_destroy",
          "name": "John Smith",
+     "username": "js",
       "user_id": 41
 }
 ```

spec/services/system_hooks_service_spec.rb

@@ -9,8 +9,8 @@ describe SystemHooksService, services: true do
   let(:group_member)  { create(:group_member) }
 
   context 'event data' do
-    it { expect(event_data(user, :create)).to include(:event_name, :name, :created_at, :updated_at, :email, :user_id) }
-    it { expect(event_data(user, :destroy)).to include(:event_name, :name, :created_at, :updated_at, :email, :user_id) }
+    it { expect(event_data(user, :create)).to include(:event_name, :name, :created_at, :updated_at, :email, :user_id, :username) }
+    it { expect(event_data(user, :destroy)).to include(:event_name, :name, :created_at, :updated_at, :email, :user_id, :username) }
     it { expect(event_data(project, :create)).to include(:event_name, :name, :created_at, :updated_at, :path, :project_id, :owner_name, :owner_email, :project_visibility) }
     it { expect(event_data(project, :destroy)).to include(:event_name, :name, :created_at, :updated_at, :path, :project_id, :owner_name, :owner_email, :project_visibility) }
     it { expect(event_data(project_member, :create)).to include(:event_name, :created_at, :updated_at, :project_name, :project_path, :project_path_with_namespace, :project_id, :user_name, :user_email, :access_level, :project_visibility) }