completed SMS gateway project

app/jobs/check_gateway_health_job.rb

@@ -0,0 +1,14 @@
+class CheckGatewayHealthJob < ApplicationJob
+  queue_as :default
+
+  def perform
+    # Mark gateways as offline if no heartbeat in last 2 minutes
+    offline_count = Gateway.where("last_heartbeat_at < ?", 2.minutes.ago)
+                          .where.not(status: "offline")
+                          .update_all(status: "offline")
+
+    if offline_count > 0
+      Rails.logger.warn("Marked #{offline_count} gateways as offline due to missing heartbeat")
+    end
+  end
+end