I'm working on a writing project with a friend, and we're looking for some kind of (preferably cloud-based) project management and version control software so each of us can see how far the other has gotten on tasks and can review each others' documents. Does anything like that exist? I would prefer free, but will pay for software that meets my needs exactly (I've got a free solution I don't like at the moment).
Edit: To be clearer, I'm looking for something where I can, say, assign a task to myself or my partner, set a due date, and keep tabs on the progress, with files being uploaded into the system upon completion of the task, to be kept in version control so if we make an edit we don't like we can roll back. We're doing a lot of world documentation, character references, and other non-chapter files we'll be working with frequently.