Makes user unwatch what he can no longer view after its permissions have changed (#3589).

A rake task (redmine:watchers:prune) is also added to prune existing watchers.

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@3167 e93f8b46-1217-0410-a6f0-8f06a7374b81

lib/tasks/watchers.rake

@@ -0,0 +1,9 @@
+desc 'Removes watchers from what they can no longer view.'
+
+namespace :redmine do
+  namespace :watchers do
+    task :prune => :environment do
+      Watcher.prune
+    end
+  end
+end