Here is the code to create a target scheme.
scheme = Xcodeproj::XCScheme.new
scheme.add_build_target(target)
scheme.set_launch_target(target)
scheme.save_as(xcode_proj_dir, name)
How to create a scheme for Today Extension?
There are some differences: Today Extension scheme locates in xcuserdata instead of xcshareddata and Executable should be Ask on Launch.
Ok, I did it like this:
scheme = Xcodeproj::XCScheme.new
scheme.add_build_target(target)
scheme.build_action.add_entry(Xcodeproj::XCScheme::BuildAction::Entry.new(app_target))
scheme.test_action.add_macro_expansion(Xcodeproj::XCScheme::MacroExpansion.new(target))
scheme.launch_action.launch_automatically_substyle = "2"
scheme.profile_action.buildable_product_runnable = Xcodeproj::XCScheme::BuildableProductRunnable.new(app_target, 0)
scheme.save_as(xcode_proj_dir, widget_name)