HOWTO Configure Google authentication

Google was chosen as the primary authentication method because the main target audience of this app is people with mobile phones mapping on the go, and apparently all mobile phones have a Google account.

Quick Links: Guide - Console

For the authentication to work, a client id is needed. It can be requested in the Google APIs console, following this guide. The client id then needs to be put in src/utils/config.ts for the frontend, then the app needs to be compiled. No other actions needed to be taken.

A few notes:

• Note that the client id is not secret, anyone can see it, that's OK. But you should configure it in the Google APIs to restrict access from sites other than your own. Otherwise anyone can use your client id, exhaust your quota, and you'd have to pay to continue letting the users log in.
• The authentication app is in testing mode by default, limited to 100 active users. If you expect more than 100 users, you have to publish the app, file it for verification by Google.