Add docs for overriding the boot method

[iSWORD]

Hi, thanks for the easy to use package!

I had to modify the boot method in one of my models to add global scopes but then I found out that Uuids were no longer being generated, so I solved it like this:

use Uuids {
    boot as protected uuid_boot;
}

instead of:

use Uuids;

then in the modified boot method:

protected static function boot()
{
    parent::boot();
    self::uuid_boot();

    // static::addGlobalScope(...);
}

Please add this somewhere in the readme/docs/whatever. Thank you!

[EmadAdly]

I'd accept a PR with tests that fixes this.