Add https://github.com/go-on/wrap

Used the similar description as muxchain because there are only so many ways you can describe a middlewares package without being biased, but exactly the same description looks weird.

README.md

@@ -433,8 +433,9 @@ Please take a quick gander at the [contribution guidelines](https://github.com/a
 *Libraries for creating HTTP middlewares.*
 
 * [alice](https://github.com/justinas/alice) - Painless middleware chaining for Go.
+* [go-wrap](https://github.com/go-on/wrap) - Small middlewares package for net/http.
 * [muxchain](https://github.com/stephens2424/muxchain) - Lightweight middleware for net/http.
-* [negroni](https://github.com/codegangsta/negroni) - Idiomatic HTTP Middleware for Golang.
+* [negroni](https://github.com/codegangsta/negroni) - Idiomatic HTTP middleware for Golang.
 * [render](https://github.com/unrolled/render) - Go package for easily rendering JSON, XML, and HTML template responses.