Is there a way to add variables to the user entity?

I'm trying to add another variable to the user entity. I want the user to be able to click a button and save their current location for later use. However, I can't seem to be able to find a way to edit the user entity. Right now I am using something like this:

var savedLocation = {
				"latitude": lat,
				"longitude": lng
			};


			var ql = "username='" + username + "'";
			var user = new Apigee.Collection({ 
				'client':client, 
				'type':'users', 
				'qs': {
					'ql': ql 
				}
			});
			user.fetch(
				function(err, data){
					if (err){
						console.log("read failed");				
					}else{
						while(user.hasNextEntity()){
							var currentUser = user.getNextEntity();
							currentUser.savedLocation = savedLocation;
							currentUser.save();
						}
					}
				}
			);


			user.savedLocation = savedLocation;

Is there a way to do this or am just going to have to create a separate database for user's saved locations?