code: function addUser(username) {
  		return userProject.findOne({'username': username}).exec()
  		.then(function(doc) {
  			if (!doc) {
  				return userProject.create(userProjectJSON(username));
  			}
  			return Promise.resolve(doc);
  		});
  	}
docs: START OF HELPER FUNCTIONS* 
  adds user if not exists.