The web is moving to HTML 5 where SVG images are the standard images to use. But how to generate SVG images to include? You might draw static SVG images and include them in your web site but this will not help with generated SVG images with dynamic data. Of course, you can read the complete specification of SVG and generate your own images; these are a few hundreds of pages; good luck with that :)
The elegant solution is to use Rasem, a pure ruby gem, to generate SVG images. Rasem allows you to describe your SVG images in pure ruby code. You can either save the generated image to a file or output it to a string to use it with your HTML 5 page. Rasem generates standard SVG images that are compliant with the W3C standard.