Rename mattermost_service to mattermost_integration

This renames the mattermost project association from mattermost_service
to mattermost_integration

app/models/integration.rb

@@ -49,6 +49,7 @@ class Integration < ApplicationRecord
     hangouts_chat
     irker
     packagist pipelines_email pivotaltracker pushover
+    mattermost
   ].to_set.freeze
   def self.renamed?(name)

app/models/project.rb

@@ -174,7 +174,7 @@ def self.integration_association_name(name)
   has_one :irker_integration, class_name: 'Integrations::Irker'
   has_one :jenkins_service, class_name: 'Integrations::Jenkins'
   has_one :jira_service, class_name: 'Integrations::Jira'
-  has_one :mattermost_service, class_name: 'Integrations::Mattermost'
+  has_one :mattermost_integration, class_name: 'Integrations::Mattermost'
   has_one :mattermost_slash_commands_service, class_name: 'Integrations::MattermostSlashCommands'
   has_one :microsoft_teams_service, class_name: 'Integrations::MicrosoftTeams'
   has_one :mock_ci_service, class_name: 'Integrations::MockCi'

spec/lib/gitlab/import_export/all_models.yml

@@ -379,7 +379,7 @@ project:
 - asana_integration
 - slack_service
 - microsoft_teams_service
-- mattermost_service
+- mattermost_integration
 - hangouts_chat_integration
 - unify_circuit_service
 - buildkite_integration

spec/models/project_spec.rb

@@ -37,7 +37,7 @@
     it { is_expected.to have_many(:exported_protected_branches) }
     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(:mattermost_integration) }
     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) }

spec/requests/api/services_spec.rb

@@ -254,21 +254,21 @@ def deactive_service!
     end
   end
-  describe 'Mattermost service' do
-    let(:service_name) { 'mattermost' }
+  describe 'Mattermost integration' do
+    let(:integration_name) { 'mattermost' }
     let(:params) do
       { webhook: 'https://hook.example.com', username: 'username' }
     end
     before do
-      project.create_mattermost_service(
+      project.create_mattermost_integration(
         active: true,
         properties: params
       )
     end
     it 'accepts a username for update' do
-      put api("/projects/#{project.id}/services/#{service_name}", user), params: params.merge(username: 'new_username')
+      put api("/projects/#{project.id}/services/#{integration_name}", user), params: params.merge(username: 'new_username')
       expect(response).to have_gitlab_http_status(:ok)
       expect(json_response['properties']['username']).to eq('new_username')