Firebase cloud messaging with next js demo

##How to get started

1. Create a firebase project

2. Edit the following files with configuration keys that are specific to your firebase project (server.js) which is at the root, the (Index.js) at the pages directory, the (server.js) which is at the credentials folder the (firebase-messaging-sw.js) which is at the static folder

3. Start the dev server.

4. Write something in the index page input box, open a new tab, wait for 6 seconds and a notification will be sent to you with what you posted in the input box as the title of the notification