README request - include example using URI.regexp about sinatra-param

[mattt]

This is indeed a cool use of existing functionality, and one that I hadn't considered previously. Thanks for sharing, @hangtwenty.

As for whether this should go in the README, that's hard to say. I'm leaning towards not for the following reasons:

• It requires an extra require
• It doesn't seem to fit with the current example of a search endpoint
• Referrers are typically sent as an HTTP header, rather than in the URL query
• Matching URI.regexp doesn't actually imply that a valid URL; most HTTP implementations limit the length of a URL to 2038 characters, however the following statement still returns true: URI.regexp.match? "http://a.com/" + ("a" * 5000)

All of that said, I think the documentation could do a better job of explaining how one might initialize domain or model objects from parameters, and what the relationship is there. I'm looking into how this could be improved in a future version.