Update CONTRIBUTING.md

Added text about "Purple Labels".  Highlighted "Issues Only"

Author: christopherthielen

CONTRIBUTING.md

@@ -1,5 +1,5 @@
 
-## Report an Issue
+# Report an Issue
 
 Help us make UI-Router better! If you think you might have found a bug, or some other weirdness, start by making sure
 it hasn't already been reported. You can [search through existing issues](https://github.com/angular-ui/ui-router/search?q=wat%3F&type=Issues)
@@ -18,10 +18,20 @@ is a bug, it's best to talk it out in the
 [StackOverflow](http://stackoverflow.com/questions/ask?tags=angularjs,angular-ui-router) before reporting it. This
 keeps development streamlined, and helps us focus on building great software.
 
-Please keep in mind that the issue tracker is for *issues*. Please do *not* post an issue if you need help or support. Instead, see one of the above-mentioned forums or [IRC](irc://irc.freenode.net/#angularjs).
 
+Issues only! |
+-------------|
+Please keep in mind that the issue tracker is for *issues*. Please do *not* post an issue if you need help or support. Instead, see one of the above-mentioned forums or [IRC](irc://irc.freenode.net/#angularjs). |
 
-## Contribute
+####Purple Labels
+A purple label means that **you** need to take some further action.  
+ - ![Not Actionable - Need Info](http://angular-ui.github.io/ui-router/images/notactionable.png): Your issue is not specific enough, or there is no clear action that we can take. Please clarify and refine your issue.
+ - ![Plunkr Please](http://angular-ui.github.io/ui-router/images/plunkrplease.png): Please [create a plunkr](http://plnkr.co/edit/u18KQc?p=preview)
+ - ![StackOverflow](http://angular-ui.github.io/ui-router/images/stackoverflow.png): We suspect your issue is really a help request, or could be answered by the community.  Please ask your question on [StackOverflow](http://stackoverflow.com/questions/ask?tags=angularjs,angular-ui-router).  If you determine that is an actual issue, please explain why.
+ 
+If your issue gets labeled with purple label, no further action will be taken until you respond to the label appropriately.
+
+# Contribute
 
 **(1)** See the **[Developing](#developing)** section below, to get the development version of UI-Router up and running on your local machine.
 
@@ -38,7 +48,7 @@ Please keep in mind that the issue tracker is for *issues*. Please do *not* post
 
 
 
-## Developing
+# Developing
 
 UI-Router uses <code>grunt >= 0.4.x</code>. Make sure to upgrade your environment and read the
 [Migration Guide](http://gruntjs.com/upgrading-from-0.3-to-0.4).