suggest a contributing guide as a best practice

[k-doering-NOAA]

This may already be included. I think a contributing guide could include details about how to contribute as well as what terms you are agreeing to when you contribute:

referencing the Github terms of service, which provide that "Whenever you add Content to a repository containing notice of a license, you license that Content under the same terms, and you agree that you have the right to license that Content under those terms. If you have a separate agreement to license that Content under different terms, such as a contributor license agreement, that agreement will supersede."

By definition, this is already the case for any repos we put on github, but this would reinforce it.