Apps-Script-Gmail-Push-Notifications-v2 | updated version of Gmail Push Notifications | Notification library

Create a new Apps Script project using the two .gs files in this repo.
Add the following libraries:     PubSubApp - 1BX8k4tkiA3CZGIZ0hHccfiF7o-EvjqLCt3hoU3osDQBhnGlQTRnawOGE     GSApp - 1wkfv_Mm0IyruEZyPZsrctcSmc1T9y0-bArl2gIzMd6RVYJAwWeJ5gpDu
Publish the project as a web app
Register the web app in the Chrome web store leaving it in draft mode. This will verifiy ownership of the script.
Run the script from the cuurrent web app URL. (the /exec one). You will get an error about no doGet(). Copy the URL it redirected you toward.
Add the URL to the WEBHOOK_URL var in main.gs
Open up the project developers console:     a) Under Credentials -> Domain Verification: Add the url you copied in WEBHOOK_URL in step 6 ommiting the exec from the end     b) Create a new service account. Download the credentials as json.     c) Under Overview: Enable the PubSub API and the Gmail API     d) Copy the json credentials and paste it into script properties under the key jsonKey.
Copy the developers console project Id to PROJECTID var in main.gs
Create a spreadsheet. Create a sheet called Log. Copy the file Id and paste it in SpreadsheetApp.openById() of doPost().
Update the webapp version to pick up changes made to the project.