Can you add buttons to navigation bars through storyboard?

At the moment, I've been adding navigation buttons like follows:

self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:@"Add"
                                                                          style:self.editButtonItem.style 
                                                                         target:self
                                                                         action:@selector(doneButtonPressed)];

It seems a bit silly to not add them through storyboard, but I can't find a way to do so. Is there one that I'm missing?

You can just drag out a Bar Button Item and drop it on the right end of the view controller's navigation bar:

As of Xcode 6, it looks like the navigation item on the navigation bar is no longer created automatically.

You'll need to drag out a Navigation Item onto the navigation bar first before you can drag out a Bar Button Item (as detailed in Rob's answer) to add to the navigation item.