Add URL Variable Rules

[dougblack]

In many RESTful APIs, there is data stored in the URI. sleepy should be able to parse it out.

For example

/users/1

can be expressed as

/users/:id

and then id could be passed to the matching resource method as a url.Values key-value pair.

[L1fescape]

Hey @dougblack, I started working on a fix for this issue here. It works as you proposed where

/users/1

expressed as

/users/:id

will add a key id with a value of 1 to url.Values.

For the most part it's working, but there are somethings I could do better. If anyone has any suggestions, let me know! In the mean time I'll be fixing bugs with it and polishing up the code, then submitting a pull request.