Choose a license and add a licence file

[cbm755]

I asked the three original authors about licensing:

Brian, Joel, Richard,

Would it be ok to post the Math 152 notes publicly, on GitHub.com or similar, under a "Creative Commons" license?

Specifically, CC-BY-SA which requires attribution and requires derivative works be similarly licensed. With those restrictions, commercial use is allowed: for example someone else can publish and sell a hardcopy but they would need to share their edits back to the community.

If you have strong feelings about licensing, happy to discuss: that was just my suggestion.

I have a positive response from all three.

[cbm755]

Just adding that a copy of the cover page from 2018 says:

© 2017 Richard Froese and Brian Wetton. Permission is
granted to make and distribute copies of this document
provided the copyright notice and this permission notice are
preserved on all copies.

So we see the document was already freely distributable. The CC-BY-SA makes is editable as well.