A rectangle with a label.

Supported `attrs` properties

Selector | Node | Description
--- | --- | ---
root | SVGGElement | Container of all nodes
body | SVGRectElement | Rectangular body of the shape
label | SVGTextElement | Text inside the body

    var rectangle = new joint.shapes.standard.Rectangle();
    rectangle.resize(100, 100);
    rectangle.position(50, 10);
    rectangle.attr('root/title', 'joint.shapes.standard.Rectangle');
    rectangle.attr('label/text', 'Rectangle');
    rectangle.attr('body/fill', 'lightblue');
    rectangle.addTo(graph);