Adding grid_table block

In order to change the table class, something like this in my template:

 ```
{% block grid%}
    {% block grid_table %}
        <table class="table table-striped">
            {% if grid.isTitleSectionVisible %}
                {{ grid_titles(grid) }}
            {% endif %}
            {% if grid.isFilterSectionVisible %}
                {{ grid_filters(grid) }}
            {% endif %}
            {{ grid_rows(grid) }}
        </table>
    {% endblock %}
{% endblock %}
 ```