sift through Settings.bundle for default values and register as user defaults. makes use of NSArray category from Mantle: https://github.com/github/Mantle/blob/master/Mantle/NSArray%2BMTLHigherOrderAdditions.h

gistfile1.m

- (BOOL)application:(UIApplication*)application didFinishLaunchingWithOptions:(NSDictionary*)launchOptions {
    // set default preferences from Settings.bundle
    NSURL* plistURL = [[[NSBundle mainBundle] URLForResource:@"Settings" withExtension:@"bundle"] URLByAppendingPathComponent:@"Root.plist"];
    if (!plistURL) {
        NSLog(@"ERROR - failed to find 'Settings.bundle/Root.plist' within main bundle");
    } else {
        NSArray* specifiers = [NSDictionary dictionaryWithContentsOfURL:plistURL][@"PreferenceSpecifiers"];
        NSDictionary* defaults = [specifiers mtl_foldLeftWithValue:[NSMutableDictionary dictionary] usingBlock:^id(NSMutableDictionary* left, NSDictionary* right) {
            if (right[@"Key"] && right[@"DefaultValue"]) {
                left[right[@"Key"]] = right[@"DefaultValue"];
            }
            return left;
        }];
        [[NSUserDefaults standardUserDefaults] registerDefaults:defaults];
    }

    return YES;
}