Fix broken links on serialization and deserialization index pages. (#21)

Author: aniketschneider

source/guides/deserialization/index.html.md

@@ -11,5 +11,5 @@ Once your deserializable resources are defined, you can call them on hashes
 representing input JSON API payloads, and obtain a hash that you can use
 directly to create/update your models.
 
-- [Defining deserializable resources](guides/deserialization/defining.html)
-- [Deserializing payloads](guides/deserialization/deserializing.html)
+- [Defining deserializable resources](/guides/deserialization/defining.html)
+- [Deserializing payloads](/guides/deserialization/deserializing.html)

source/guides/serialization/index.html.md

@@ -14,5 +14,5 @@ Once your serializable resources are defined, you can pass your business objects
 to the *renderer*, that will build the appropriate serializable resources, and
 render them into a JSON API document.
 
-- [Defining serializable resources](guides/serialization/defining.html)
-- [Rendering JSON API documents](guides/serialization/rendering.html)
+- [Defining serializable resources](/guides/serialization/defining.html)
+- [Rendering JSON API documents](/guides/serialization/rendering.html)