Fix migration refering to different column type (unsigned/signed)
<?php

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

class CreateParticipantsTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('participants', function (Blueprint $table) {
            $table->increments('id');
            $table->integer('draw_id')->unsigned();
            $table->text('santa');
            $table->text('challenge');

            $table->foreign('draw_id')->references('id')->on('draws')->onDelete('cascade');
        });
    }

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

<?php

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

class CreateParticipantsTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('participants', function (Blueprint $table) {
            $table->increments('id');
            $table->integer('draw_id');
            $table->text('santa');
            $table->text('challenge');

            $table->foreign('draw_id')->references('id')->on('draws')->onDelete('cascade');
        });
    }

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