Add RGraph

[heyesr]

Read about RGraph here: https://www.rgraph.net It's canvas/SVG/JavaScript based, supports lots of chart types and is quite mature (started in 2008).

Cheers.

[igorlukanin]

Hey @heyesr 👋 Thanks for the suggestion! Could you please take a look at https://github.com/cube-js/awesome-tools/tree/master/copy/tools and submit a PR that adds RGraph? Thanks in advance!

[heyesr]

Hi there,

I've added the rgraph.yml file via a pull request. No idea why the checks failed though... :-(