Ask user what to do with child pages when deleting a parent wiki page (#3202).

3 options are available:
* move child pages as root pages
* move child pages to another parent page
* delete all descendants

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@2676 e93f8b46-1217-0410-a6f0-8f06a7374b81

vendor/plugins/acts_as_tree/lib/active_record/acts/tree.rb

@@ -40,11 +40,11 @@ module ActiveRecord
         # * <tt>order</tt> - makes it possible to sort the children according to this SQL snippet.
         # * <tt>counter_cache</tt> - keeps a count in a +children_count+ column if set to +true+ (default: +false+).
         def acts_as_tree(options = {})
-          configuration = { :foreign_key => "parent_id", :order => nil, :counter_cache => nil }
+          configuration = { :foreign_key => "parent_id", :dependent => :destroy, :order => nil, :counter_cache => nil }
           configuration.update(options) if options.is_a?(Hash)
 
           belongs_to :parent, :class_name => name, :foreign_key => configuration[:foreign_key], :counter_cache => configuration[:counter_cache]
-          has_many :children, :class_name => name, :foreign_key => configuration[:foreign_key], :order => configuration[:order], :dependent => :destroy
+          has_many :children, :class_name => name, :foreign_key => configuration[:foreign_key], :order => configuration[:order], :dependent => configuration[:dependent]
 
           class_eval <<-EOV
             include ActiveRecord::Acts::Tree::InstanceMethods
@@ -77,6 +77,13 @@ module ActiveRecord
           children + children.collect(&:children).flatten
         end
 
+        # Returns list of descendants and a reference to the current node.
+        #
+        #   root.self_and_descendants # => [root, child1, subchild1, subchild2]
+        def self_and_descendants
+          [self] + descendants
+        end
+
         # Returns the root node of the tree.
         def root
           node = self