Redis cache best practice

Hello everyone.

I'm using Redis as caching system and it works great for most of the part, I've a little question tho

I've an index() method which contains this code

        $companies = Cache::rememberForever('auth.companies', function () {
            return Company::with([
                'tags',
                'emails'
            ])->get();
        });

This should store the companies inside the key auth.companies, and it works fine. The doubt appears when I try to edit a specific company in update() method like so

$company = Company::whereId($id)->firstOrFail();
$company->update($request->all());
Cache::forget('auth.companies');

My questions are

• When I try to update a specific entity should i work with the cached object or retrieve it from the Database? (which is NOT redis atm)
• If I should work with the cached object how can I persist the data inside the Database?

EDIT: typos