Support for DatabaseMigration for Testing

[eezhal92]

This PR is created because I can't use Illuminate\Foundation\Testing\DatabaseMigrations with doctrine in functional test.

If we take a look to the code, it just execute eloquent migrations. I create this trait in order to able migrate doctrine migrations.

<?php

use LaravelDoctrine\Migrations\Testing\DatabaseMigrations;

class AFeatureTest extends TestCase
{
   use DatabaseMigrations;
}