Delete node_modules from repo.
Git ignore node_modules.
Make server log what port to connect to.
Make static files get re-read from disk on every request.

* Less efficient, but means you don't need to restart the server on every client side JS change.
No need to hardcode server when loading socket.io client lib.
Make game.js include URL more explicit.
Whitespace.
Good style example.

* Haven't changed this everywhere.  Good style is:
  Space between if and (
  Space between ) and {
  Space between } and else if
  Space between } and else
  Space between else and {
No need to put server in module - node sandboxes JS vars inside files.
Group together event handling functions into eventHandlers.
Put server startup code into its own fn.
Change init() to initSocketIO().

* Only handles setting up socket.io.
Now init() does not set up players array, do that in main server code.
Call initSocketIO() when server code runs.

* Do not init socket like it is a widely used global.
Call setEventHandlers now it is not called by init()

* Pass socket.
Move game loop running into new startGame() fn
Call startGame() to start game.
Remove loop and time globals.
Add isInPlayArea() fn to ball. Returns true if ball between floor and ceiling.
Stop ball.update() returning whether game is over.

* Want to separate responsibilities of the fn.