checks.rb in mongoid-2.3.1

- old
+ new

@@ -5,9 +5,21 @@
 
       # This module has object checks in it.
       module Checks #:nodoc:
         attr_accessor :unconvertable_to_bson
 
+        # Is the string a valid value for a Mongoid id?
+        #
+        # @example Is the string an id value?
+        #   "_id".mongoid_id?
+        #
+        # @return [ true, false ] If the string is id or _id.
+        #
+        # @since 2.3.1
+        def mongoid_id?
+          self =~ /^(|_)id$/
+        end
+
         # Is the object not to be converted to bson on criteria creation?
         #
         # @example Is the object unconvertable?
         #   object.unconvertable_to_bson?
         #