Documentation for wildcard hash filter

[Rick Carlino]

Hi,

I needed to write a hash attribute that was a dynamic key/value lookup.

After examining the source, I noticed that you can do wildcard filters, but the feature was not documented.

I've added documentation to the wiki. Apologies if I have misunderstood the feature. I am raising this issue in hopes that someone will proof read my work.

Keep up the great work on this project.

[Eugene Kenny]

This is extremely overdue, but thanks @RickCarlino - the example you added looks good. 👌