[imac] fcoury:~/dev → ruby mongo_bug.rb
	{"id"=>"4b07e771e999fb0a0b000002", "user_id"=>{"data"=>[75, 7, 231, 113, 233, 153, 251, 10, 11, 0, 0, 1]}, "ip"=>"200.192.200.11", "ip_address"=>nil}

	/usr/local/lib/ruby/gems/1.8/gems/mongo-0.17.1/lib/mongo/types/objectid.rb:73:in `from_string': illegal ObjectID format (RuntimeError)
	        from /usr/local/lib/ruby/gems/1.8/gems/mongo_mapper-0.6.1/lib/mongo_mapper/types.rb:38:in `to_mongo'
	        from /usr/local/lib/ruby/gems/1.8/gems/mongo_mapper-0.6.1/lib/mongo_mapper/key.rb:17:in `set'
	        from /usr/local/lib/ruby/gems/1.8/gems/mongo_mapper-0.6.1/lib/mongo_mapper/embedded_document.rb:374:in `write_attribute'
	        from /usr/local/lib/ruby/gems/1.8/gems/mongo_mapper-0.6.1/lib/mongo_mapper/dirty.rb:123:in `write_attribute'
	        from (eval):10:in `user_id='
	        from /usr/local/lib/ruby/gems/1.8/gems/mongo_mapper-0.6.1/lib/mongo_mapper/embedded_document.rb:231:in `send'
	        from /usr/local/lib/ruby/gems/1.8/gems/mongo_mapper-0.6.1/lib/mongo_mapper/embedded_document.rb:231:in `attributes='
	        from /usr/local/lib/ruby/gems/1.8/gems/mongo_mapper-0.6.1/lib/mongo_mapper/embedded_document.rb:227:in `each_pair'
	        from /usr/local/lib/ruby/gems/1.8/gems/mongo_mapper-0.6.1/lib/mongo_mapper/embedded_document.rb:227:in `attributes='
	        from /usr/local/lib/ruby/gems/1.8/gems/mongo_mapper-0.6.1/lib/mongo_mapper/embedded_document.rb:200:in `initialize'
	        from /usr/local/lib/ruby/gems/1.8/gems/mongo_mapper-0.6.1/lib/mongo_mapper/dirty.rb:50:in `initialize'
	        from mongo_bug.rb:37:in `new'
	        from mongo_bug.rb:37