Submission of my coding challenge result

Please check out the revised README where I outline my approach, and include further documentation and screenshots. 
To summarize the README, my solution contains two approaches:
1) The first configuration loads the dataset into memory via a file stream when the app initializes. API requests will search via the JavaScript object in memory. The file system is only read once.
2) The second configuration will retrieve the data from MongoDB for every API request. Nothing is stored in memory. This is enabled via the USE_MONGO=true environment variable. 

I also created a web test harness using Express and Jade on the back-end, and jQuery on the front-end. This feature added time to my project submission, but I think the results are worth it for real-world testing of the API. You can try it now on Heroku at http://mighty-wildwood-7373.herokuapp.com/apitest.