As developers, one of the best things you can do for a project is to use version control (or "source control") for your code. Lorna Mitchell suggest using it on a wider scale, though. She sees it as a great place for all sorts of other things around a project too.
Short answer: everything! However we need some good directory structures and source control configuration to make that a really practical answer, so this article is a quick outline of my usual advice for a good source control structure for a standard web project. The examples are for a PHP project but I'm sure you could apply this to your own language of choice, also.
These "other things" she suggests that should end up in source control including things like:
- The actual "web root" of your application
- Library code
- Build scripts
- Configuration files
- Database patches
- Tests (unit, functional, integration, etc)