Add documentation to changelog

Author: Ives van Hoorne

packages/homepage/content/changelog/2017-12-14-documentation.md

@@ -0,0 +1,10 @@
+---
+title: "Documentation"
+authors: ["CompuIves"]
+---
+
+We now have a proper documentation. You can find all CodeSandbox related info here, from API information to how to use features.
+
+![Documentation](./images/documentation.png)
+
+You can find it [here](/docs).