In order to deploy this application, make sure that you have been added to the firebase project. Also make sure that you are logged in with the same firebase account in the firebase tools on the command line. From there you just type firebase deploy and everything is good to go!
If you are just deploying the functions you can run firebase deploy --only functions so you do not need to deploy everything.
If you are fixing any issues, or adding new features to this application, please for it and make PR's from there.