joomla 3- com_contact add new fields

Joomla 3.1
Com_contact
Contact add new field example is Phone Number view
1. Add new field Phone to form
 components\com_contact\views\contact\tmpl\default_form.php

<div class="control-group">
                <div class="control-label"><?php echo JText::_('COM_CONTACT_EMAIL_LABEL'); ?></div>
                <div class="controls"><?php echo $this->form->getInput('contact_email'); ?></div>
                <div class="clr"></div>
            </div>
            <div class="control-group">
                <div class="control-label"><?php echo JText::_('COM_CONTACT_PHONE_LABEL'); ?></div>
                <div class="controls"><input type="text"  size="60" value="" id="jform_contact_phone" name="jform[contact_phone]" ></div>
                <div class="clr"></div>
            </div>
            <div class="control-group">
                <div class="control-label"><?php echo JText::_('COM_CONTACT_CONTACT_MESSAGE_SUBJECT_LABEL'); ?></div>
                <div class="controls"><?php echo $this->form->getInput('contact_subject'); ?></div>
                <div class="clr"></div>
            </div>
2. Send mail : add new content to mail body
files: components\com_contact\controllers\contact.php at function private function _sendEmail
Replace: line 156-161:
            $phone = 'Phone Number:  '.$data['contact_phone'];
            $body        = $data['contact_message'];

            // Prepare email body
            $prefix = JText::sprintf('COM_CONTACT_ENQUIRY_TEXT', JUri::base());
            $body    = $prefix."\n".$name.' <'.$email.'>'."\r\n\r\n".$phone."\n".stripslashes($body);
Result is: