SQL tutorial

[gvwilson]

We'd like your help to build and improve a lesson on SQL! If you would like to help out, please file issues in this repository about bugs or shortcomings in the existing SQL lessons, or suggestions for additional lessons. Pull requests are also very welcome, and everyone who contributes will be acknowledged in the author list.

[Haleshot]

Thanks again for creating this! Anyone specific you have in mind to contribute towards such lessons (any interested students you're overseeing, volunteers, etc.) or is it more of an open call?

Edit: I see it mentioned in the course README.