http://marklodato.github.com/visual-git ... ex-en.html Is also a very good resource on git in general.
Git makes it very easy to make polo the 'gate keeper' and he is able to validate all code that is compiled, and make beta versions for testing, before rolling the final results into production code.
Git is very very good at handling the whole idea of reviewing code, testing it in 'non-stable' or 'beta' versions, and then giving one person the ability to control what ends up in the production code.
Git is also special, because unlike other tools it looks at changes as 'objects' instead of 'files' so multiple changes to different files, are treated as one big change. It's pretty amazing actually.