If you've been using Git for a while, you might be wondering how it actually works. In the first video of the Mastering Git video course, you'll discover how Git is built on top of a simple key-value store-based file system, and what power this provides to you.
There are currently no plans to add a tutorial on that, no. GitHub has recently launched some new features that support restrictions on things like merges and pushing. That might be what you’re looking for.
git itself has functionality to run scripts at different points using git-hooks—you could use these to ensure that commits pass some arbitrary tests.
xcodeproj are frustratingly difficult to resolve conflicts in. In my experience there are only really 2 approaches (same for storyboards):
Since xcodeproj is just XML, if a conflict is simple, you can resolve it by opening it in a text editor, locating the conflicts and fixing them manually.
Choose one of the versions—usually the “before”, and then zip through Xcode recreating the changes.
It all depends on the scenario. (2) can be irritating, but is sometimes the only real way to properly resolve the issues. If commits are kept small, it’s often not too challenging to resolve these issues.