README.md: Fix typo in "serializer" (#65)

Author: msabramo

README.md

@@ -2,7 +2,7 @@
 
 [![Build Status](https://travis-ci.org/google/jsonapi.svg?branch=master)](https://travis-ci.org/google/jsonapi)
 
-A serailizer/deserializer for json payloads that comply to the
+A serializer/deserializer for json payloads that comply to the
 [JSON API - jsonapi.org](http://jsonapi.org) spec in go.
 
 Also visit, [Godoc](http://godoc.org/github.com/google/jsonapi).