This is really a combined tutorial, stemmed from the amazing Jared Hanson and Pedro Teixeira. I just wanted to take a couple of examples one step further and produce a working Twitter authentication project using a Mongo database. Make sure you check out the tech, this is a common (and really fun) stack:

Node
Express
Mongoose
Passport

Check out my Github repo for the code. If you don't have Mongo installed, head over their Quickstart page. After you clone the repo, create a location for the Mongo data.

~/Sites/twitter-mongo : mkdir data

Next, in another terminal start the Mongo database using the new data location.

~/Sites/twitter-mongo : mongod --dbpath ./data/

Last thing to do is put in your Twitter consumer key and consumer secret in the "app.js" file (make a Twitter app). Run node.

~/Sites/twitter-mongo : node app.js