Clean up Spot routes

[jadnco]

This issue mostly has to do with this:

router.route('/users/:id/spots')
  .get((req, res) => {
    User.getSpots(req.params.id, req, res);
  })
  .post((req, res) => {
    Spot.create(req.params.id, req, res);
  })
  .delete((req, res) => {
    Spot.remove(req.params.id, req, res);
  });

What I need to figure out is:

• Does a new Spot get created at users/:id/spots or just /spots
• Does the spotter id association come from the :id in the URL or is it sent as part of the body.