ConstructionFormType.php

<?php

namespace CliCons\ExtranetBundle\Form\Type;

use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\FormBuilderInterface;
use Symfony\Component\OptionsResolver\OptionsResolverInterface;

class ConstructionFormType extends AbstractType
{
        /**
     * @param FormBuilderInterface $builder
     * @param array $options
     */
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder
            ->add('name')
            ->add('description')
            ->add(
                'address',
                'clicons_extranetbundle_address',
                array('label' => false,'required' => false)
            )
            ->add('workers', 'collection', array(
                    'type' => new ConstructionWorkerFormType(),
                    'allow_add'    => true,
                ))
            ->add('register', 'submit',array('label' => 'form.user.registration.register'));

        ;
    }
    
    /**
     * @param OptionsResolverInterface $resolver
     */
    public function setDefaultOptions(OptionsResolverInterface $resolver)
    {
        $resolver->setDefaults(array(
            'data_class' => 'CliCons\CoreBundle\Entity\Construction'
        ));
    }

    /**
     * @return string
     */
    public function getName()
    {
        return 'clicons_extranetbundle_construction';
    }
}

ConstructionWorkerFormType.php

<?php

namespace CliCons\ExtranetBundle\Form\Type;

use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\FormBuilderInterface;
use Symfony\Component\OptionsResolver\OptionsResolverInterface;
use CliCons\CoreBundle\Enum\PrincipalAgentTypeEnum;

class ConstructionWorkerFormType extends AbstractType
{
        /**
     * @param FormBuilderInterface $builder
     * @param array $options
     */
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder
            ->add('principalAgentType','choice', array('choices' =>PrincipalAgentTypeEnum::getTranslations() ))
            ->add('user','genemu_jqueryselect2_entity', array('class' => 'CliCons\CoreBundle\Entity\User', 'property'=>'companyName',
                ))


        ;
    }
    
    /**
     * @param OptionsResolverInterface $resolver
     */
    public function setDefaultOptions(OptionsResolverInterface $resolver)
    {
        $resolver->setDefaults(array(
            'translation_domain' => 'extranet',
            'data_class' => 'CliCons\CoreBundle\Entity\ConstructionWorker'
        ));
    }

    /**
     * @return string
     */
    public function getName()
    {
        return 'clicons_extranetbundle_constructionworker';
    }
}

edit.html.twig

{% extends "@CliConsExtranet/extranet.html.twig" %}

{% block stylesheets %}
    {{ parent() }}
    {% stylesheets filter='cssrewrite'
    'bundles/cliconsextranet/css/ui/jquery-ui.min.css'
    'bundles/cliconsextranet/css/extranet.css'
    'bundles/cliconsadmin/css/select2.css'
    %}
    <link href="{{ asset_url }}" type="text/css" rel="stylesheet" media="screen"/>
    {% endstylesheets %}
    {% if form is defined %}
        {{ form_stylesheet(form) }}
    {% endif %}
{% endblock %}

{% block javascripts %}
    {{ parent() }}
    <script src="http://maps.google.com/maps/api/js?sensor=false&language=es"></script>

    {%- javascripts
    '@CliConsExtranetBundle/Resources/public/js/jquery.min.js'
    '@CliConsExtranetBundle/Resources/public/js/ui/jquery-ui.min.js'
    '@CliConsExtranetBundle/Resources/public/js/ui/jquery.ui.addresspicker.js'
    '@CliConsAdminBundle/Resources/public/js/select2.js'

    filter="" %}
    <script src="{{ asset_url }}"></script>
    {% endjavascripts %}
    {% if form is defined %}
    {{ form_javascript(form) }}
    {% endif %}

{% endblock %}


{% block content %}

    {% block id 'usuario22' %}

        {% block article %}
            <h1>{{ block('title') }}</h1>
            {{ form_start(form) }}
            {{ form_row(form.name) }}
            {{ form_row(form.description) }}
            {{ form_row(form.address) }}

            <h3>workers</h3>
            <ul class="workers" data-prototype="{{ form_widget(form.workers.vars.prototype)|e }}">
            </ul>
            {{ form_end(form) }}
        {% endblock %}

        <div class='map-wrapper'>
            <div id="map"></div>
            <div id="legend">You can drag and drop the marker to the correct location</div>
        </div>

        <div class='input-positioned'>
            <label>Callback: </label>
            <textarea id='callback_result' rows="15"></textarea>
        </div>


<script type="text/javascript">
    // Get the ul that holds the collection of tags
    var collectionHolder = $('ul.workers');

    // setup an "add a tag" link
    var $addTagLink = $('<a href="#" class="add_tag_link">Add a tag</a>');
    var $newLinkLi = $('<li></li>').append($addTagLink);

    $(function (){
        // add the "add a tag" anchor and li to the tags ul
        collectionHolder.append($newLinkLi);

        // count the current form inputs we have (e.g. 2), use that as the new
        // index when inserting a new item (e.g. 2)
        collectionHolder.data('index', collectionHolder.find(':input').length);

        $addTagLink.on('click', function (e) {
            // prevent the link from creating a "#" on the URL
            e.preventDefault();

            // add a new tag form (see next code block)
            addTagForm(collectionHolder, $newLinkLi);
        });
    });
    function triggerJavascript(id)
    {
        $field = $('#' + id);


        {{ form_javascript(form.workers.vars.prototype, true) }}
    }
    function addTagForm(collectionHolder, $newLinkLi) {
//            Get the data-prototype explained earlier
        var prototype = collectionHolder.data('prototype');

        // get the new index
        var index = collectionHolder.data('index');

        // Replace '__name__' in the prototype's HTML to
        // instead be a number based on how many items we have
        var newForm = prototype.replace(/__name__/g, index);

        // increase the index with one for the next item
        collectionHolder.data('index', index + 1);

        // Display the form in the page in an li, before the "Add a tag" link li
        var $newFormLi = $('<li></li>').append(newForm);
        $newLinkLi.before($newFormLi);

        // Dynamically add the form and get its id
        var id = '{{ form.workers.vars.id }}_' + id;

        // Once HTML has been added, let's trigger the javascript on it
            triggerJavascript(id);
        {##}

    }
</script>

{% endblock %}