Doctrine embeddables issue

Address.php

<?php

namespace AppBundle\Entity;

use Doctrine\ORM\Mapping as ORM;

/** @ORM\Embeddable */
class Address
{
    /** @ORM\Column(type = "string") */
    private $street;

    /** @ORM\Column(type = "string") */
    private $city;

    public function setStreet($value)
    {
        $this->street = $value;
        return $this;
    }

    public function getStreet()
    {
        return $this->street;
    }

    public function setCity($value)
    {
        $this->city = $value;
        return $this;
    }

    public function getCity()
    {
        return $this->city;
    }
}

composer.json

{
    "name": "symfony/framework-standard-edition",
    "license": "MIT",
    "type": "project",
    "description": "The \"Symfony Standard Edition\" distribution",
    "autoload": {
        "psr-0": { "": "src/", "SymfonyStandard": "app/" }
    },
    "require": {
        "php": ">=5.3.3",
        "symfony/symfony": "2.6.*",
        "doctrine/orm": "2.5.*@dev",
        "doctrine/common": "2.5.*@dev",
        "doctrine/doctrine-bundle": "~1.2",
        "twig/extensions": "~1.0",
        "symfony/assetic-bundle": "~2.3",
        "symfony/swiftmailer-bundle": "~2.3",
        "symfony/monolog-bundle": "~2.4",
        "sensio/distribution-bundle": "~3.0.12",
        "sensio/framework-extra-bundle": "~3.0",
        "incenteev/composer-parameter-handler": "~2.0"
    },
    "require-dev": {
        "sensio/generator-bundle": "~2.3"
    },
    "scripts": {
        "post-root-package-install": [
            "SymfonyStandard\\Composer::hookRootPackageInstall"
        ],
        "post-install-cmd": [
            "Incenteev\\ParameterHandler\\ScriptHandler::buildParameters",
            "Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::buildBootstrap",
            "Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::clearCache",
            "Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::installAssets",
            "Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::installRequirementsFile",
            "Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::removeSymfonyStandardFiles"
        ],
        "post-update-cmd": [
            "Incenteev\\ParameterHandler\\ScriptHandler::buildParameters",
            "Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::buildBootstrap",
            "Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::clearCache",
            "Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::installAssets",
            "Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::installRequirementsFile",
            "Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::removeSymfonyStandardFiles"
        ]
    },
    "config": {
        "bin-dir": "bin"
    },
    "extra": {
        "symfony-app-dir": "app",
        "symfony-web-dir": "web",
        "symfony-assets-install": "relative",
        "incenteev-parameters": {
            "file": "app/config/parameters.yml"
        },
        "branch-alias": {
            "dev-master": "2.6-dev"
        }
    }
}

User.php

<?php

namespace AppBundle\Entity;

use Doctrine\ORM\Mapping as ORM;

/**
 * @ORM\Table()
 * @ORM\Entity
 */
class User
{
    /**
     * @ORM\Column(name="id", type="integer")
     * @ORM\Id
     * @ORM\GeneratedValue(strategy="AUTO")
     */
    private $id;

    /** @ORM\Column(name="username", type="string", length=255) */
    private $username;

    /** @ORM\Embedded(class="Address") */
    private $address;

    public function getId()
    {
        return $this->id;
    }

    public function setUsername($username)
    {
        $this->username = $username;

        return $this;
    }

    public function getUsername()
    {
        return $this->username;
    }

    public function setAddress($address)
    {
        $this->address = $address;
        return $this;
    }

    public function getAddress()
    {
        return $this->address;
    }
}