Documentation directory needs a tutorial

[thomashoneyman]

Is your change request related to a problem? Please describe.
As described in the documentation section of the Library Guidelines, Contributors libraries are expected to have some documentation in the docs directory -- specifically, at least a short tutorial that expands on the quick start in the README.

This library currently doesn't have comprehensive documentation in the docs directory.

Describe the solution you'd like
At least a short tutorial needs to be added to the docs directory, or other documentation as described in this Divio article.

The argonaut-codecs docs directory has a good example of expanded documentation for a Contributor library. But it would even be useful to add something considerably smaller and shorter to this library.

Additional context
See the Governance repository for more information about requirements in the Contributors organization.