Add migration for new fields in project index

We are adding few new fields to project index to build new filters
on the search page for users.

app/services/projects/detect_repository_languages_service.rb

@@ -66,3 +66,5 @@ def set_detected_repository_languages
     end
   end
 end
+
+Projects::DetectRepositoryLanguagesService.prepend_mod_with('Projects::DetectRepositoryLanguagesService')

ee/app/services/ee/projects/detect_repository_languages_service.rb

+# frozen_string_literal: true
+
+module EE
+  module Projects
+    module DetectRepositoryLanguagesService
+      def execute
+        repository_languages = super
+        project.maintain_elasticsearch_update if project.maintaining_elasticsearch?
+
+        repository_languages
+      end
+    end
+  end
+end

ee/spec/services/ee/projects/detect_repository_languages_service_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Projects::DetectRepositoryLanguagesService, :clean_gitlab_redis_shared_state, feature_category: :groups_and_projects do
+  let_it_be_with_reload(:project) { create(:project, :repository) }
+
+  describe '#execute' do
+    context 'without previous detection' do
+      before do
+        stub_ee_application_setting(elasticsearch_indexing?: true)
+      end
+
+      it 'calls ProcessBookkeepingService' do
+        expect(::Elastic::ProcessBookkeepingService).to receive(:track!).with(project).once
+        described_class.new(project).execute
+      end
+    end
+  end
+end