activeadmin#1587 documenting need to migrate to new dashboard registr…

…ation to avoid uninitialized constant Admin::DashboardController

README.rdoc

@@ -4,7 +4,7 @@ Active Admin is a framework for creating administration style interfaces. It
 abstracts common business application patterns to make it simple for developers
 to implement beautiful and elegant interfaces with very little effort.
 
-{<img src="https://secure.travis-ci.org/gregbell/active_admin.png?branch=master" />}[http://travis-ci.org/gregbell/active_admin] {<img src="https://codeclimate.com/badge.png" />}[https://codeclimate.com/github/gregbell/active_admin] {<img src="https://gemnasium.com/gregbell/active_admin.png" />}[https://gemnasium.com/gregbell/active_admin]
+{<img src="https://secure.travis-ci.org/gregbell/active_admin.png?branch=master" />}[http://travis-ci.org/gregbell/active_admin] {<img src="https://codeclimate.com/badge.png" />}[https://codeclimate.com/github/gregbell/active_admin]
 
 == Documentation & Support
 
@@ -78,6 +78,11 @@ Refresh your web browser to see the interface.
 When upgrading to a new version of ActiveAdmin you may need to run
   $> rails generate active_admin:assets
 
+If you get:
+  uninitialized constant Admin::DashboardController
+when trying to view the dashboard (at +/admin+), ensure +app/admin/dashboards.rb+ looks like the current {default}[https://raw.github.com/gregbell/active_admin/master/lib/generators/active_admin/install/templates/dashboard.rb].
+
+
 == Next Steps
 
 The best place to get documentation is at http://activeadmin.info/documentation.html.