Initial DB Integration via Bookshelf and Knex

This pull request covers a few different aspects of the server, as follows.  It is by no means complete, but merging it could help us build on top of this tomorrow rather than wasting time with bookshelf integrations:

1) Added a dbConfig.example.js file that has the structure we will need for our actual database integration.  The real file will be saved as dbConfig.js and added to the .gitignore

2) Built a couple basic implementations in the user controller for functions that could be written in the Model.  Alternately, we may decide to simply implement the functionality in the controller once we've set up the bookshelf schema.

3)  Did some work in userModel.js to demonstrate how we will export and declare a user table schema.  The actual schema data still needs to be filled out.

4)  Added postgreSQL dependencies in the package.json along with bookshelf and knex.