<div class="row">
    <div class="col-sm-6">
        <div class="form-group">
            <label class="form-label">{{ form_label(form.user.username) }}</label>
            {{ form_widget(form.user.username) }}
        </div>
    </div>
    <div class="col-sm-6">
        <div class="form-group">
            <label class="form-label">{{ form_label(form.user.email) }}</label>
            {{ form_widget(form.user.email) }}
        </div>
    </div>
</div>
<div class="row">
    <div class="col-sm-6">
        <div class="form-group">
            <label class="form-label">{{ form_label(form.user.lastName) }}</label>
            {{ form_widget(form.user.lastName) }}
        </div>
    </div>
    <div class="col-sm-6">
        <div class="form-group">
            <label class="form-label">{{ form_label(form.user.firstName) }}</label>
            {{ form_widget(form.user.firstName) }}
        </div>
    </div>
</div>

