Documented the auth

Author: David Yell

README.md

@@ -46,6 +46,14 @@ Save them into the `/app/database` folder and run the seeder `artisan db:seed St
 
 The project includes [GraphIQL](https://github.com/mll-lab/laravel-graphiql). You can make use of the client by installing Composer `dev` dependencies and then visiting http://localhost/graphiql.
 
+### Authentication
+
+The `/graphql` endpoint is secured with a Laravel Sanctum token auth. You will need to login and generate a token, and send this token with your requests as the Authorization header.
+
+```http request
+Authorization: Bearer <your-token>
+```
+
 ### Example queries
 
 Get all the cards, but only a few fields, paginated by 20 per page on page 4, and include the set the card belongs to.