Add Marketing Resources to Sales Handbook.

source/handbook/sales/index.html.md

@@ -43,6 +43,7 @@ title: "Sales Handbook"
 * [Resellers Handbook](/handbook/resellers/)
 * [Customer Reference Sheet](https://docs.google.com/a/gitlab.com/spreadsheets/d/1Off9pVkc2krT90TyOEevmr4ZtTEmutMj8dLgCnIbhRs/edit?usp=sharing)
 * [Sales Collateral](https://drive.google.com/open?id=0B-ytP5bMib9TaUZQeDRzcE9idVk)
+* [Marketing Resources (whitepapers, webcasts, blog posts etc.)](https://about.gitlab.com/resources/)
 * [Sales Training](https://drive.google.com/open?id=0B41DBToSSIG_WU9LZ0o0ektEd0E)
 * [Lead Gen Content Resources](https://about.gitlab.com/resources/)
 * [GitLab University](https://university.gitlab.com/)