Add contributor docs for our ZenHub usage

Signed-off-by: Ross Kukulinski <ross@kukulinski.com>

README.md

@@ -2,7 +2,7 @@
 
 **Maintainers:** [Heptio][0]
 
-[![Build Status][1]][2]
+[![Build Status][1]][2] <a href="https://zenhub.com"><img src="https://raw.githubusercontent.com/ZenHubIO/support/master/zenhub-badge.png"></a>
 
 ## Overview
 
@@ -35,6 +35,7 @@ Feedback and discussion is available on [the mailing list][24].
 
 * Please familiarize yourself with the [Code of Conduct][8] before contributing.
 * See [CONTRIBUTING.md][5] for instructions on the developer certificate of origin that we require.
+* Read how [we're using ZenHub](26) for project and roadmap planning
 
 ### Pull requests
 
@@ -62,6 +63,7 @@ See [the list of releases][6] to find out about feature changes.
 
 [24]: http://j.hept.io/ark-list
 [25]: https://kubernetes.slack.com/messages/ark-dr
+[26]: https://github.com/heptio/ark/blob/master/docs/zenhub.md
 
 
 [29]: https://heptio.github.io/ark/

docs/zenhub.md

@@ -0,0 +1,15 @@
+# ZenHub
+
+As an Open Source community, it is necessary for our work, communication, and collaboration to be done in the open.
+GitHub provides a central repository for code, pull requests, issues, and documentation.  When applicable, we will use Google Docs for design reviews, proposals, and other working documents.
+
+While GitHub issues, milestones, and labels generally work pretty well, the Heptio team has found that product planning requires some additional tooling that GitHub projects do not offer.  
+
+In our effort to minimize tooling while enabling product management insights, we have decided to use [ZenHub Open-Source](https://www.zenhub.com/blog/open-source/) to overlay product and project tracking on top of GitHub.
+ZenHub is a GitHub application that provides Kanban visualization, Epic tracking, fine-grained prioritization, and more.  It's primary backing storage system is existing GitHub issues along with additional metadata stored in ZenHub's database.
+
+If you are an Ark user or Ark Developer, you do not _need_ to use ZenHub for your regular workflow (e.g to see open bug reports or feature requests, work on pull requests).  However, if you'd like to be able to visualize the high-level project goals and roadmap, you will need to use the free version of ZenHub.
+
+## Using ZenHub
+
+ZenHub can be integrated within the GitHub interface using their [Chrome or FireFox extensions](https://www.zenhub.com/extension).  In addition, you can use their dedicated [web application](app.zenhub.com).