bookstack/database/migrations/2023_07_31_104430_create_watches_table.php

<?php

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

return new class extends Migration
{
    /**
     * Run the migrations.
     */
    public function up(): void
    {
        Schema::create('watches', function (Blueprint $table) {
            $table->increments('id');
            $table->integer('user_id')->index();
            $table->integer('watchable_id');
            $table->string('watchable_type', 100);
            $table->tinyInteger('level', false, true)->index();
            $table->timestamps();

            $table->index(['watchable_id', 'watchable_type'], 'watchable_index');
        });
    }

    /**
     * Reverse the migrations.
     */
    public function down(): void
    {
        Schema::dropIfExists('watches');
    }
};