Update user.js

- Do not use a temp var here (`var type = req.files.userPhoto.type;`), that's just wasting memory since we're only using it once (and it isn't helping readability all that much)
- Add notes about console.error use, indicate it's temporary and needs replaced with proper logging
- Indicate that resizing code should be split out into another process (perhaps with node's built in cluster module? or child_process.spawn?)
- Do not use `res.send` with JSON data; use res.json
- Use consistent spacing and whitespace usage