Vignette - adding a new index

[leppott]

Is your feature request related to a problem? Please describe.
Users need capability to add a new index.

Describe the solution you'd like
Add a vignette for adding a new index.

Describe alternatives you've considered
Can't have users throwing up their hands or always having the author add it. Need to make the package easier for users to use and extend.

Additional context
Include how to send back to author to get added to the package. (pull request)
Also need info on how to set up a test for the new index.

[leppott]

Can use Colorado as an example since have a request for it.