undoocumented API_URL and STRAVA_CLIENT about startertab

[allister-grange]

Hey @Magniquick, there is a section in the ReadMe that goes over all of the integrations. It's the Current API Integrations section, you'll see in there links to the APIs that the application uses, from those links you'll be able to create your own API auth keys.

STRAVA_CLIENT_ID is the client ID for authentication with Strava's API.

API_URL is used for local hosting purposes, it's a reference to the url of the API. This is so that I can use an env variable to point my local instance at different environments for testing.

Let me know if you have any other questions!