Use expose_path to add relative url

app/presenters/packages/composer/packages_presenter.rb

@@ -11,8 +11,8 @@ module Packages
       end
 
       def root
-        path = api_v4_group___packages_composer_package_name_path({ id: @group.id, package_name: '%package%$%hash%', format: '.json' }, true)
-        { 'packages' => [], 'provider-includes' => { 'p/%hash%.json' => { 'sha256' => provider_sha } }, 'providers-url' => ENV['RAILS_RELATIVE_URL_ROOT'] ? ENV['RAILS_RELATIVE_URL_ROOT'] + path : path }
+        path = expose_path(api_v4_group___packages_composer_package_name_path({ id: @group.id, package_name: '%package%$%hash%', format: '.json' }, true))
+        { 'packages' => [], 'provider-includes' => { 'p/%hash%.json' => { 'sha256' => provider_sha } }, 'providers-url' => path }
       end
 
       def provider