How to add new field in "servers" table?

[rasm945i]

It's probably very simple, but I'm trying to add a new field in the "servers" table, a "next_checkup" field.
I've looked far and wide across a bunch of files, also tried editing a few, but with no luck. It's probably some Laravel thing that I need to know, but I have no clue what to search for as I've already tried.
I'd like the value included in API requests. I've tried the following so far, without luck:

Had a glance at ServerTransformer.php in /app/Transformers/Api/ (Client/Application) folders. It seems like I need to do something in here.

In app/Models/Server.php
Added * @property \Carbon\Carbon $next_checkup
under the other @property things with dates

Added public const NEXT_CHECKUP = self::UPDATED_AT; and I honestly have no clue if that works as I think it should (sets the default value to the same as updated_at)

Included the "next_checkup" field on the following lines:
protected $dates = [self::CREATED_AT, self::UPDATED_AT, self::NEXT_CHECKUP, 'deleted_at'];
protected $guarded = ['id', self::CREATED_AT, self::UPDATED_AT, self::NEXT_CHECKUP, 'deleted_at'];

Added 'next_checkup' => 'present|nullable|date' at the bottom of the $validationRules map

Added 'next_checkup' => 'date', in the $casts map

Whenever I've tried something new, I run the following commands to make sure it is up-to-date

composer install --no-dev --optimize-autoloader
php artisan view:clear
php artisan config:clear
php artisan migrate --seed --force    // this one says "nothing to migrate" all the time

And yes, I'm kinda just throwing spaghetti at the wall hoping it sticks since I'm unsure where to start and what to look out for. Any help is greatly appreciated.

[TekExplorer]

you would need to add a migration. take a look at pterodactyl's existing migrations to see how they work