I was wondering why updating to 2.6 broke my app
then I checked the diff and saw

v2.5.1...v2.6.0

+    def level
+      self.ancestors.size
+    end

my app already uses level to store the depth

CREATE TABLE regions (
    id integer NOT NULL,
    name character varying,
    level integer,
    parent_id integer,
);

any suggestion for how to avoid this name conflict?