Wrap Prometheus initializer into Rails Executor

lib/prometheus/controller.rb

@@ -13,13 +13,13 @@ module Prometheus
         register_metrics
 
         Rails.application.eager_load!
+        Rails.application.executor.wrap do
           Thread.new do
             initialize_instance_count
             initialize_rfc_metrics
           rescue StandardError => e
             Sentry.capture_exception(e)
-        ensure
+          end
-          ActiveRecord::Base.connection_pool.release_connection
         end
       end