Adding Xcode Workspace Schemes to Version Control
Choose Manage Schemes from the Schemes control. Check "Shared" beside any schemes you'd like to share. The schemes will be moved into a folder called "xcshareddata".
Update: This works the same for Xcode 4-8.
You'll need to go into the "Manage Schemes" view and check off the 'Shared' checkbox ('Product' menu -> Scheme -> Manage Schemes...).
Next, You'll need to remove 'xcshareddata/xcschemes' from your ignore file and add them to the repo (or just use 'git add -f MyProject.xcodeproj/xcshareddata/xcschemes')