Add siesta to frameworks

Author: Preetam

README.md

@@ -317,3 +317,4 @@ If the HttpRouter is a bit too minimalistic for you, you might try one of the fo
 * [Medeina](https://github.com/imdario/medeina): Inspired by Ruby's Roda and Cuba
 * [Neko](https://github.com/rocwong/neko): A lightweight web application framework for Golang
 * [Roxanna](https://github.com/iamthemuffinman/Roxanna): An amalgamation of httprouter, better logging, and hot reload
+* [siesta](https://github.com/VividCortex/siesta): Composable HTTP handlers with contexts