Merge pull request #1 from anandwana001/patch-1

fix screenshot size

-mention the article readme

-notifications show using sender name and picture instead of receiver's

Merge remote-tracking branch 'origin/master'

-apk added

Delete google-services.json

-readme and screenshots added

-firebase cloud function finalized (sends notifications to receivers)

-firebase cloud function init (dispatches messages to sender and receiver)

readme init

-init commit