BookStack/database/migrations/2016_05_06_185215_create_attributes_table.php

<?php

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

class CreateAttributesTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('attributes', function (Blueprint $table) {
            $table->increments('id');
            $table->integer('entity_id');
            $table->string('entity_type', 100);
            $table->string('name');
            $table->string('value');
            $table->integer('order');
            $table->timestamps();

            $table->index('name');
            $table->index('value');
            $table->index('order');
            $table->index(['entity_id', 'entity_type']);
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::drop('attributes');
    }
}