In order to use the authentication for APIs, create a file authentication.properties in src\main\resources directory.
Inside place the following contents:
vatsim.client-secret = <CLIENT_SECRET>
vateud.api.key = <API_KEY>
db.host = <HOST>
db.port = <PORT>
db.schema = <SCHEMA>
db.username = <USERNAME>
db.password = <PASSWORD>