title: Sending notification to the user on database change
body: <p>I am building a cafeteria management system in which there are two types of users;customres &amp; counter owners.</p>
  
  <p>For each dish offered in cafeteria, there is aunique dish.id associated to it.</p>
  
  <p>Till now, I have dome something like student sends a POST request with dish,id and counter number to a URL which updates the "orders table'(which has PK as id). When the dish is prepared, the counter owner presses "Prepeared" button.</p>
  
  <p>At this point, I want the customer whose order is next to what is prepared to get notified that "Your order preparation is in progress."</p>
  
  <p>How should I do it?
  One way is to simply make a view which has its argument as customer.id &amp; status and it replies with True or Flase. I can simply poll the URL and provide the notification if I recieve True.</p>
  
  <p><strong>But, I feel like polling is not a better approach as there will be so many customers logged in and each will poll to the server which is not acceptible</strong>.
  Any better way?</p>