Postgres 9.4 Add INDEX USING GIN
<p>I am using Postgres 9.4, JSONB fields, those are working good.
But when I add GIN index doctrine migration fails to created index.</p>

<pre><code>class Version20160314132147_Gin_Indexes_content   extends AbstractMigration {

public function up(Schema $schema) {
    $this-&gt;addSql('CREATE INDEX contents_properties_ix ON contents USING gin (properties);');
}

/**
 * @param Schema $schema
 */
public function down(Schema $schema) {
    $this-&gt;addSql('DROP INDEX contents_properties_ix;');
}
}
</code></pre>

<p>Error:
[Doctrine\DBAL\Driver\PDOException]
  SQLSTATE[42704]: Undefined object: 7 ERROR:  data type json has no default operator class for access method "gin"
  HINT:  You must specify an operator class for the index or define a default operator class for the data type.</p>

<p>Composer.json
    {
        "slim/slim": "~2.6",
        "doctrine/orm": "~2.5",
        "doctrine/dbal": "2.5",
        "symfony/yaml": "2.8.<em>@dev",
        "doctrine/cache": "~1.5@dev",
        "symfony/console": "2.8.</em>@dev",
        "symfony/class-loader": "^2.7.4",
        "doctrine/migrations": "~1.0",
        "predis/predis": "~1.0.1",
        "guzzlehttp/guzzle": "~5.0",
        "twig/twig": "~1.0",
        "php-di/php-di": "^5.1.0",
        "monolog/monolog": "~1.15@dev",
        "boldtrn/jsonb-bundle": "~1.0",
        "opsway/doctrine-dbal-postgresql": "~0.1",
        "fzaninotto/faker": "~1.3.0",
        "aws/aws-sdk-php": "^3.9"
    }</p>