add project members to export

app/services/projects/import_export.rb

@@ -7,7 +7,7 @@ module Projects
     end
 
     def project_atts
-      %i(id name path description issues_enabled wall_enabled merge_requests_enabled wiki_enabled snippets_enabled visibility_level archived)
+      %i(project_members name path description issues_enabled wall_enabled merge_requests_enabled wiki_enabled snippets_enabled visibility_level archived)
     end
 
     def project_tree

spec/services/projects/import_export/project_tree_saver_spec.rb

@@ -81,6 +81,10 @@ describe Projects::ImportExport::ProjectTreeSaver, services: true do
       it 'has commit statuses' do
         expect(saved_project_json['commit_statuses']).not_to be_empty
       end
+
+      it 'has project members' do
+        expect(saved_project_json['commit_statuses']).not_to be_empty
+      end
     end
   end