How to use ProMotion-Menu?

I did an new project only with the code shown in the Promotion-Menu's Readme. I have this :

# app_delegate.rb
class AppDelegate < PM::Delegate
  def on_load(app, options)
    @menu = open MenuDrawer
  end

  def show_menu
    @menu.show :left
  end
end

#menu_drawer.rb
class MenuDrawer < PM::Menu::Drawer

  def setup
    self.center = HomeScreen.new(nav_bar: true)
    self.left = NavigationScreen
    self.to_show = [:pan_bezel, :pan_nav_bar]
    self.transition_animation = :swinging_door
    self.max_left_width = 250
    self.shadow = false
  end

end

#navigation_screen.rb
class NavigationScreen < ProMotion::TableScreen

  def table_data
    [{
      title: nil,
      cells: [{
        title: 'OVERWRITE THIS METHOD',
        action: :swap_center_controller,
        arguments: HomeScreen
      }]
    }]
  end

  def swap_center_controller(screen_class)
    app_delegate.menu.center_controller = screen_class
  end

end

My app is running but there is no sidebar as you can see here :

Did I miss something ?

No. What you have there should be working. You'll have to pan the bezel or nav bar to reveal the left controller (which is hidden when you first open the app). I've been thinking about adding a menu button to the examples to make this a little bit clearer. Here's how that might work:

# home_screen.rb
class HomeScreen < PM::Screen
  title "Home"

  def on_load
    set_nav_bar_button :right, title: "Menu", action: :open_menu
  end

  def open_menu
    app_delegate.show_menu
  end
end

# navigation_screen.rb
class NavigationScreen < ProMotion::TableScreen
  def table_data
    [{
      title: nil,
      cells: [{
        title: 'HomeScreen',
        action: :swap_center_controller,
        arguments: HomeScreen.new(nav_bar: true)
      },{
        title: 'HelpScreen',
        action: :swap_center_controller,
        arguments: HelpScreen.new(nav_bar: true)
      }]
    }]
  end

  def swap_center_controller(screen)
    app_delegate.menu.center_controller = screen
    app_delegate.menu.hide
  end
end

Your AppDelegate and MenuDrawer would remain unchanged.