add link to openstack trigger example (#484)

CHANGELOG.md

@@ -11,6 +11,7 @@
 - [#310](https://github.com/iron-io/functions/issues/310): fnctl: Add python support.
 - [#69](https://github.com/iron-io/functions/issues/69): Long(er) running containers for better performance aka Hot Containers.
 - [#472](https://github.com/iron-io/functions/pull/472): Add global lru for routes with keys being the appname + path
+- [#484](https://github.com/iron-io/functions/pull/484): Add triggers example for OpenStack project Picasso.
 
 ### Bugfixes
 

docs/operating/triggers.md

@@ -2,4 +2,21 @@
 
 Triggers are integrations that you can use in other systems to fire off functions in IronFunctions.
 
-TODO:
+## OpenStack
+
+### Requirements
+
+1. OpenStack or DevStack environment.
+
+    * OS: Ubuntu 16.04 LTS or newer
+    * Kernel: 4.7 or newer with overlay2 or aufs module
+    * Docker: 1.12 or newer
+
+2. [Picasso](https://github.com/openstack/picasso) - Picasso provides an OpenStack API and Keystone authentication layer on top of IronFunctions.
+Please refer to the [Picasso on DevStack](https://github.com/openstack/picasso/blob/master/devstack/README.md) guide for setup instructions.
+
+### Examples
+
+* [Alarm event triggers from Telemetry and Aodh](https://github.com/openstack/picasso/blob/master/examples/openstack-alarms/README.md)
+* Swift notifications - *Status: On roadmap*
+    * [Blueprint](https://blueprints.launchpad.net/picasso/+spec/swift-notifications)