Rename hangouts_chat_service to integration

This renames the project association from hangouts_chat_service to
hangouts_chat_integration.

app/models/integration.rb

@@ -46,6 +46,7 @@ class Integration < ApplicationRecord
     datadog discord drone_ci
     emails_on_push ewm emails_on_push external_wiki
     flowdock
+    hangouts_chat
   ].to_set.freeze
 
   def self.renamed?(name)

app/models/project.rb

@@ -170,7 +170,7 @@ class Project < ApplicationRecord
   has_one :ewm_integration, class_name: 'Integrations::Ewm'
   has_one :external_wiki_integration, class_name: 'Integrations::ExternalWiki'
   has_one :flowdock_integration, class_name: 'Integrations::Flowdock'
-  has_one :hangouts_chat_service, class_name: 'Integrations::HangoutsChat'
+  has_one :hangouts_chat_integration, class_name: 'Integrations::HangoutsChat'
   has_one :irker_service, class_name: 'Integrations::Irker'
   has_one :jenkins_service, class_name: 'Integrations::Jenkins'
   has_one :jira_service, class_name: 'Integrations::Jira'

spec/lib/gitlab/import_export/all_models.yml

@@ -380,7 +380,7 @@ project:
 - slack_service
 - microsoft_teams_service
 - mattermost_service
-- hangouts_chat_service
+- hangouts_chat_integration
 - unify_circuit_service
 - buildkite_integration
 - bamboo_integration

spec/models/project_spec.rb

@@ -38,7 +38,7 @@ RSpec.describe Project, factory_default: :keep do
     it { is_expected.to have_one(:slack_service) }
     it { is_expected.to have_one(:microsoft_teams_service) }
     it { is_expected.to have_one(:mattermost_service) }
-    it { is_expected.to have_one(:hangouts_chat_service) }
+    it { is_expected.to have_one(:hangouts_chat_integration) }
     it { is_expected.to have_one(:unify_circuit_service) }
     it { is_expected.to have_one(:webex_teams_service) }
     it { is_expected.to have_one(:packagist_service) }

spec/requests/api/services_spec.rb

@@ -317,7 +317,7 @@ RSpec.describe API::Services do
     end
 
     before do
-      project.create_hangouts_chat_service(
+      project.create_hangouts_chat_integration(
         active: true,
         properties: params
       )