Fix that Example plugin (extra/sample_plugin) breaks Activity page (#38114).

Patch by Karel Pičman.


git-svn-id: https://svn.redmine.org/redmine/trunk@22079 e93f8b46-1217-0410-a6f0-8f06a7374b81

Author: vividtone

extra/sample_plugin/app/models/meeting.rb

@@ -7,6 +7,6 @@ class Meeting < ActiveRecord::Base
                 :url => Proc.new {|o| {:controller => 'meetings', :action => 'show', :id => o.id}}
 
   acts_as_activity_provider :timestamp => 'scheduled_on',
-                            :scope => proc { includes(:project) },
+                            :scope => proc { joins(:project) },
                             :permission => nil
 end