Error while creating Documents on Cloud Firestore - Permission Denied

I am trying out Cloud Firestore. I think I have done something silly, so I am not able to even to create any docs/collection, both through code and through console.

I haven't locked the DB with any write/read rules (any one can read/write) to the DB. Below is my rule configuration.

    service cloud.firestore {
  match /databases/{database}/documents {
    match /{document=**} {
      allow read, write;
    }
  }
}

When I try through console, it opens up a modal where I enter the collection name and the first document (using generated ID). Then clicking on 'Save' simply closes the modal, but the DB is not updated.

When I try to insert docs through code (JS), I could see the following error thrown on the console.

Error updating data: Error: PERMISSION_DENIED: Permission denied
at firebase-storage.js:3479
at z (firebase-storage.js:3479)
at t.callOnCompleteCallback (firebase-storage.js:3479)
at firebase-storage.js:3479
at firebase-storage.js:3479
at e.ci (firebase-storage.js:3479)
at t.ci (firebase-storage.js:3479)
at t.qi (firebase-storage.js:3479)
at e.onMessage (firebase-storage.js:3479)
at e._o (firebase-storage.js:3479)

Below is the JS code.

var config = {
  apiKey: "xxxx",
  authDomain: "xxxx.firebaseapp.com",
  databaseURL: "https://xxxx.firebaseio.com",
  projectId: "xxxx",
  storageBucket: "",
  messagingSenderId: "yyyy"
};
firebase.initializeApp(config);

var db = firebase.firestore();

$scope.addNote = function() {

  var note = {
    text: 'Sample Note',
    createdBy: 'Ranis'
  }
  db.collection('notes').add(note).then(function(data) {
      console.log('Note Added ', data)
    },
    function(err) {
      console.log('Note Add Error ', err);
    });
}