Adds security notice to README

README.md

@@ -1,3 +1,13 @@
+# Security Notice
+
+There is a known SECURITY VULNERABILITY in the current release and previous releases of this software. Please contact [email protected] for information on how to fix this vulnerability if you have it deployed publicly.
+
+We will fix the vulnerability in the code in this GitHub repository in the next 2 weeks (by May 29th, 2017) but are giving current users of the software time to implement the fix before releasing it publicly.
+
+If you have a public installation of the software, please email info at hotosm.org for information on how to fix the bug.
+
+Please delay downloading and installing the current version of the software on a public server until the fix is merged into this repository.
+
 # OpenStreetMap Tasking Manager
 
 [![Build Status](https://travis-ci.org/hotosm/osm-tasking-manager2.svg?branch=master)](https://travis-ci.org/hotosm/osm-tasking-manager2)