How to report a score or achievement? - ios

Question

The Game Center tutorial I was following showed me everything except how to report the scores and achievements to the leaderboards.
This is the score part:
+ (void)reportScore:(Float64) score forIdentifier: (NSString*) identifier {
GKScore* highScore = [[GKScore alloc] initWithLeaderboardIdentifier:#"Tap_Competition_LB"];
highScore.value = score;
[GKScore reportScores:#[highScore] withCompletionHandler:^(NSError *error) {
if (error) {
NSLog(#"Error in reporting scores: %#", error);
}
}];
}
and this is the achievement part:
+ (void) reportAchievementIdentifier: (NSString*) identifier percentComplete: (float) percent
{
GKAchievement *achievement = [[GKAchievement alloc] initWithIdentifier: identifier];
if (achievement)
{
achievement.percentComplete = percent;
achievement.showsCompletionBanner = YES;
if (![[NSUserDefaults standardUserDefaults] boolForKey:identifier]) {
//Tell analytics if you want to
}
NSArray *achievements = #[achievement];
[GKAchievement reportAchievements:achievements withCompletionHandler:^(NSError *error) {
if (error != nil) {
NSLog(#"Error in reporting achievements: %#", error);
} else {
[[NSUserDefaults standardUserDefaults] setBool:YES forKey:identifier];
[[NSUserDefaults standardUserDefaults] synchronize];
}
}];
}
}
Which are both located in the TCUser file I've created, after the authentication of the local user.
The tutorial I was following gave this line of code for reporting:
[SingletonClassName reportAchievementIdentifier:#"com.companyname.gamename.achievementname" percentComplete:100.0f];
But I don't understand which singleton class to reference. Can anyone help me out and show me how exactly to report a score or achievement?
The Apple documentation didn't help either.
PS This was the tutorial: http://www.raywenderlich.com/forums/viewtopic.php?f=2&t=10844