text: Q:
  
  MongoDB add event
  
  Is it possible to somehow subscribe to 'add to db' event using Node.js? Database is currently populated via Ruby on Rails. Thanks.
  
  A:
  
  MongoDB wise
  There's an ongoing discussion about triggers on mongodb Jira.
  But for now you're stuck with storing auto-increment values alongside with your data, and using indexed queries to check if there's anything new.
  Rails wise
  I'm assuming you're using Mongoid. Use callbacks or observers to send messages to a fast capped collection / unix socket / whatever. Other ODMs shouldn't be too different.
  
  