"DEFINE SCOPE statement" Improvement

[dormammun]

Suggest to improve these docs.

DEFINE SCOPE account SESSION 24h
	SIGNUP ( CREATE user SET email = $email, pass = crypto::argon2::generate($pass) )
	SIGNIN ( SELECT * FROM user WHERE email = $email AND crypto::argon2::compare(pass, $pass) )

This statement will not work on signin because user can singup with duplicated email. And select statement will return two users.

        log(await db.signup({
            NS: 'test',
            DB: 'test',
            SC: 'account ',
            email : 'test',
            pass: 'test',
        }))
        // create second user with same data
        log(await db.signup({
            NS: 'test',
            DB: 'test',
            SC: 'account ',
            email : 'test',
            pass: 'test',
        }))

        console.log(await db.invalidate());

        // Error
        log(await db.signin({
            NS: 'test',
            DB: 'test',
            SC: 'account ',
            email : 'test',
            pass: 'test',
        }))

Because SELECT * FROM user WHERE email = $email AND crypto::argon2::compare(pass, $pass) returns an array of two users.

Suggestions:

1. Add limit.
   SIGNIN ( SELECT * FROM user WHERE email = $email AND crypto::argon2::compare(pass, $pass) ) LIMIT 1
   But this is bad logic for authentication.

2. Return meaningful error because without debugging it is hard to understand what's wrong.
   Original error:

Error: There was a problem with authentication
    at WebSocketStrategy.signup (c:\Users\khote\Dev\sandbox\surreal\node_modules\surrealdb.js\script\strategies\websocket.js:121:19)
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
    at <anonymous> (c:\Users\khote\Dev\sandbox\surreal\index.ts:41:13)

3. Improve doc description with additional user table configuration.

        DEFINE TABLE user SCHEMALESS;
        DEFINE INDEX userUsernameIndex ON TABLE user COLUMNS username UNIQUE;
        
        DEFINE SCOPE auth SESSION 24h
            SIGNUP ( CREATE user SET username = $username, password = crypto::argon2::generate($password) )
            SIGNIN ( SELECT * FROM user WHERE username = $username AND crypto::argon2::compare(password, $password) )
            ;
            
            DEFINE TABLE article SCHEMALESS
                PERMISSIONS 
                    FOR create
                        WHERE author = $auth.id
                    FOR select
                        WHERE author = $auth.id;

Thank you for great database 👍
I'm really looking forward to your release v1. And I beg you to add different business cases/examples/scenarios for documentation. :)

Question:
When I create article in the last scenario with db.create don't create a record and don't emit error.

        log(await db.create('article', {title: 'Goodbye', content: 'No text', author: '$auth.id'})) // don't create/emit error; returns empty array.
        log(await db.query(`CREATE article CONTENT { title: "Hello World", content: "This is a test article", author: $auth.id }`)) // creates record

I can guess that in the first request I need somehow get a user ID and pass it to the object. But when I signin I get only a token without the ability to retrieve the user by the token. So, I require 1-st: authenticate user, and 2-nd: fetch him again by credentials to get ID. Is there a workaround?