node.js + Express code critique
Your code looks fine.

However, you are not showing us much to review, definitely come back when there is more to review.

Some minor comments:


Having your db connection config through ./config/db is good
You probably want to throw an exception if ( typeof cb !== "function" ) instead of silently ignoring that
The base/db code nests 4 levels of callback, you should look into queue management libraries for node.js