Fixes Google issue 12 by providing a clear message on auth failure

app/controllers/sessions_controller.rb

@@ -30,4 +30,8 @@ def failure
     redirect_to root_url, :alert => "Authentication error: #{params[:message].humanize}"
   end
 
+  def auth_failure
+    #things
+  end
+
 end

app/views/sessions/auth_failure.html.erb

@@ -0,0 +1,4 @@
+<div class="center">
+  <h1>Authorization failure :-(</h1>
+  <h3>To use ISS Flyby install it by visiting https://glass.google.com/glassware</h3>
+</div>

config/routes.rb

@@ -9,6 +9,8 @@
 	resources :spacecrafts
 
 	root :to => 'application#index'
+
+  get '/auth/failure', to: 'sessions#auth_failure'
 	get '/auth/:provider/callback', to: 'sessions#create'
 	get '/sign_in', to: 'sessions#new', as: 'sign_in'
 	get '/privacy', to: 'pages#privacy', as: 'privacy'