Add security warning re: short keys
[![Build Status](https://travis-ci.org/puppetlabs/puppetlabs-apt.png?branch=master)](https://travis-ci.org/puppetlabs/puppetlabs-apt)
-## Description
-
-Provides helpful definitions for dealing with Apt.
-
-=======
-
Overview
--------
APT automates obtaining and installing software packages on \*nix systems.
+***Note:** While this module allows the use of short keys, we STRONGLY RECOMMEND that you DO NOT USE short keys, as they pose a serious security issue in that they open you up to collision attacks.*
+
Setup
-----