normalize _id to id for mongoid

lib/orm_adapter/adapters/mongoid.rb

@@ -5,7 +5,7 @@ module Document
     module ClassMethods
       include OrmAdapter::ToAdapter
     end
-    
+
     class OrmAdapter < ::OrmAdapter::Base
       # Do not consider these to be part of the class list
       def self.except_classes
@@ -48,7 +48,7 @@ def find_all(options)
       def create!(attributes)
         klass.create!(attributes)
       end
-  
+
       # @see OrmAdapter::Base#destroy
       def destroy(object)
         object.destroy if valid_object?(object)
@@ -61,6 +61,8 @@ def conditions_to_fields(conditions)
         conditions.inject({}) do |fields, (key, value)|
           if value.is_a?(Mongoid::Document) && klass.fields.keys.include?("#{key}_id")
             fields.merge("#{key}_id" => value.id)
+          elsif key.to_s == 'id'
+            fields.merge('_id' => value)
           else
             fields.merge(key => value)
           end