Push notifications tutorial

This will only be a tutorial on implementing Push Notifications in Baker. For general information about Push Notifications, see:

• Apple Push Notification Services Tutorial: Part 1/2 by Ray Wenderlich
• Apple's own documentation About Local Notifications and Push Notifications and Newsstand FAQ

You will need an APNS device token for any device you want to send a notification to. The token is generated on the device when a user agrees to receiving push notifications when first opening an app. Baker will send the token to your server using the APNS device token endpoint.