title: MKPolyline not showing on MKMapView
body: <p>Here's the code. Its pretty straight forward. I'm making a path for someone who is walking. 
  So, here's the code for my <code>ViewController.m</code> file : </p>
  
  <pre><code>#import "ViewController.h"
  
  @interface ViewController ()
  
  @property BOOL firstTime;
  
  @end
  
  @implementation ViewController
  
  - (void)viewDidLoad
  {
      [super viewDidLoad];
      // Do any additional setup after loading the view, typically from a nib.
      [self.mapView setDelegate:self];
      [self.mapView setShowsUserLocation:YES];
      [self.mapView setMapType:MKMapTypeHybrid];
  
      [self setLocationManager:[[CLLocationManager alloc] init]];
      [self.locationManager setDelegate:self];
      [self.locationManager setDistanceFilter:kCLDistanceFilterNone];
      [self.locationManager setDesiredAccuracy:kCLLocationAccuracyBest];
      [self.locationManager startUpdatingLocation];
  
      self.index = 0;
  
      self.firstTime = YES;
  }
  
  - (void)didReceiveMemoryWarning
  {
      [super didReceiveMemoryWarning];
      // Dispose of any resources that can be recreated.
  }
  
  - (void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations
  {
      if(self.firstTime)
      {
          CLLocation *startingLocation = [locations objectAtIndex:0];
          self.startingPointCooridinates = startingLocation.coordinate;
          self.index++;
  
          MKPointAnnotation *startingPointAnnotation = [[MKPointAnnotation alloc] init];
          startingPointAnnotation.title = @"Starting Point";
          startingPointAnnotation.coordinate = startingLocation.coordinate;
  
          [self.mapView addAnnotation:startingPointAnnotation];
  
          self.firstTime = false;
      }
  
      [self.locations addObject:[locations objectAtIndex:0]];
  
      CLLocationCoordinate2D coordinates[[self.locations count]];
      for(int i = 0; i &lt; self.locations.count; i++)
      {
          CLLocation *currentLocation = [locations objectAtIndex:i];
          coordinates[i] = currentLocation.coordinate;
      }
  
      MKPolyline *pathPolyline = [MKPolyline polylineWithCoordinates:coordinates count:self.locations.count];
      [self.mapView addOverlay:pathPolyline];
  }
  
  - (MKOverlayRenderer *)mapView:(MKMapView *)mapView rendererForOverlay:(id&lt;MKOverlay&gt;)overlay
  {
      if([overlay isKindOfClass:[MKPolyline class]])
      {
          MKPolylineRenderer *polylineRenderer = [[MKPolylineRenderer alloc] initWithPolyline:overlay];
          polylineRenderer.fillColor = [[UIColor redColor] colorWithAlphaComponent:0.2];
          polylineRenderer.strokeColor = [[UIColor redColor] colorWithAlphaComponent:0.7];
          polylineRenderer.lineWidth = 2.0;
          return polylineRenderer;
      }
      else
      {
          return  nil;
      }
  }
  </code></pre>
  
  <p>Now, only the annotation is showing and there isn't any <code>MKPolyline</code> showing up. What am I doing wrong ? Thanks.</p>