New self_and_ancestors_ids method to get self id with ancestor_ids

lib/closure_tree/model.rb

@@ -86,6 +86,10 @@ def ancestor_ids
       _ct.ids_from(ancestors)
     end
 
+    def self_and_ancestors_ids
+      _ct.ids_from(ancestors) + [id]
+    end
+
     # Returns an array, root first, of self_and_ancestors' values of the +to_s_column+, which defaults
     # to the +name_column+.
     # (so child.ancestry_path == +%w{grandparent parent child}+

spec/user_spec.rb

@@ -84,8 +84,10 @@ def assert_mid_and_leaf_remain
     u = User.find_or_create_by_path(%w([email protected] [email protected] [email protected]))
     u.descendant_ids.should == []
     u.ancestor_ids.should == [u.parent.id, u.root.id]
+    u.self_and_ancestor_ids.should == [u.parent.id, u.root.id] + [u.id]
     u.root.descendant_ids.should == [u.parent.id, u.id]
     u.root.ancestor_ids.should == []
+    u.root.self_and_ancestor_ids.should == [u.root.id]
     c1 = u.contracts.create!
     c2 = u.parent.contracts.create!
     u.root.indirect_contracts.to_a.should =~ [c1, c2]