adding :prepend option to load_and_authorize_resource - closes #290

lib/cancan/controller_additions.rb

@@ -109,6 +109,9 @@ module CanCan
       #
       #     load_resource :new => :build
       #
+      # [:+prepend+]
+      #   Passing +true+ will use prepend_before_filter instead of a normal before_filter.
+      #
       def load_resource(*args)
         cancan_resource_class.add_before_filter(self, :load_resource, *args)
       end
@@ -162,6 +165,9 @@ module CanCan
       # [:+through+]
       #   Authorize conditions on this parent resource when instance isn't available.
       #
+      # [:+prepend+]
+      #   Passing +true+ will use prepend_before_filter instead of a normal before_filter.
+      #
       def authorize_resource(*args)
         cancan_resource_class.add_before_filter(self, :authorize_resource, *args)
       end

lib/cancan/controller_resource.rb

@@ -5,7 +5,8 @@ module CanCan
     def self.add_before_filter(controller_class, method, *args)
       options = args.extract_options!
       resource_name = args.first
-      controller_class.before_filter(options.slice(:only, :except)) do |controller|
+      before_filter_method = options.delete(:prepend) ? :prepend_before_filter : :before_filter
+      controller_class.send(before_filter_method, options.slice(:only, :except)) do |controller|
         controller.class.cancan_resource_class.new(controller, resource_name, options.except(:only, :except)).send(method)
       end
     end