exchange/database/migrations/2018_06_19_144347_create_marking_table.php

<?php

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

class CreateMarkingTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('markings', function (Blueprint $table) {
            $table->increments('id');
            $table->string('email')->unique();
            $table->string('marking')->unique();
            $table->timestamps();
        });
    }

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