snipe-it/database/migrations/2016_05_19_191146_add_alter_interval.php

<?php

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

class AddAlterInterval extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::table('settings', function (Blueprint $table) {
            $table->integer('alert_interval')->nullable()->default('30');
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::table('settings', function ($table) {
            $table->dropColumn(
                'alert_interval'
            );
        });
    }
}