title: Send push notifications from nodejs server
body: <p>I have a node.js server using mongoDB and I want to send push notifications to specific users in area using my ionic app. The code to find closest users is already written, but now i faced a problem how to properly store or get device tokens from users and what service to use to send notifications. I've discovered that most services need user to be registered in app database that you create via that service, but i want to store user device token in my local database. Are there any good solutions to send notifications from local server using tokens stored in local database?</p>