Problem getting relations working with HateoasBundle

Controller.php

<?php
// This is just copy pasted in here. 
class Controller {

public function getMemberAction($memberId)
{
        $country = $this->getDoctrine()->getRepository('HautelookApiBundle:Countries')->find('US');

        $serializedCountry = $this->get('serializer')->serialize($country, 'json');

        $response = new Response($serializedCountry);
        $response->headers->set('Content-Type', 'application/json');

        return $response;
}

}

Countries.php

<?php

namespace Hautelook\ApiBundle\Entity;

use Doctrine\ORM\Mapping as ORM;

use JMS\SerializerBundle\Annotation as JMSSerializer;

use FSC\HateoasBundle\Annotation as Hateoas;

/**
 * Hautelook\ApiBundle\Entity\Countries
 * @Hateoas\Relation("self", route = "hautelook_api_inspiration_getinspired")
 * @ORM\Table(name="countries")
 * @ORM\Entity
 */
class Countries implements HalResource
{
    /**
     * @var string $countryIso
     *
     * @ORM\Column(name="country_iso", type="string", length=2, nullable=false)
     * @ORM\Id
     * @ORM\GeneratedValue(strategy="IDENTITY")
     */
    private $countryIso;

    /**
     * @var string $countryIso3
     *
     * @ORM\Column(name="country_iso3", type="string", length=3, nullable=false)
     */
    private $countryIso3;

    /**
     * @var string $countryName
     *
     * @ORM\Column(name="country_name", type="string", length=80, nullable=false)
     */
    private $countryName;

    /**
     * @var Quads
     * @JMSSerializer\Type("array")
     * @ORM\ManyToMany(targetEntity="Quads", inversedBy="countryIso")
     * @ORM\JoinTable(name="shipping_country_quad_exclusions",
     *   joinColumns={
     *     @ORM\JoinColumn(name="country_iso", referencedColumnName="country_iso")
     *   },
     *   inverseJoinColumns={
     *     @ORM\JoinColumn(name="quad_id", referencedColumnName="quad_id")
     *   }
     * )
     */
    private $quad;

    public function __construct()
    {
        $this->quad = new \Doctrine\Common\Collections\ArrayCollection();
    }

    /**
     * Get countryIso
     *
     * @return string
     */
    public function getCountryIso()
    {
        return $this->countryIso;
    }

    /**
     * Set countryIso3
     *
     * @param string $countryIso3
     */
    public function setCountryIso3($countryIso3)
    {
        $this->countryIso3 = $countryIso3;
    }

    /**
     * Get countryIso3
     *
     * @return string
     */
    public function getCountryIso3()
    {
        return $this->countryIso3;
    }

    /**
     * Set countryName
     *
     * @param string $countryName
     */
    public function setCountryName($countryName)
    {
        $this->countryName = $countryName;
    }

    /**
     * Get countryName
     *
     * @return string
     */
    public function getCountryName()
    {
        return $this->countryName;
    }

    /**
     * Add quad
     *
     * @param Hautelook\ApiBundle\Entity\Quads $quad
     */
    public function addQuads(\Hautelook\ApiBundle\Entity\Quads $quad)
    {
        $this->quad[] = $quad;
    }

    /**
     * Get quad
     *
     * @return Doctrine\Common\Collections\Collection
     */
    public function getQuad()
    {
        return $this->quad;
    }
}

output.json

{
"country_iso": "US",
"country_iso3": "USA",
"country_name": "United States",
"quad": []
}