open goal corresponding to goal of tapped notification

[krugerk]

This is the app side. Rather than parsing the alert title for the slug as was done in the previous PR, this one works with the notification that provides the goalname (slug) directly as part of the user info.

On the server side, the code in #41 (comment) needs yet to be adjusted to something like the following:

-notification = Apnotic::Notification.new(token)
-notification.topic = "com.beeminder.beeminder"
-notification.alert = goal.alert_text(type)
-notification.badge = eep_count
-notification.sound = "default"
-notification.apns_collapse_id = goal.shortname
+
+notification = Apnotic::Notification.new(token)
+notification.topic = "com.beeminder.beeminder"
+notification.alert = goal.alert_text(type)
+notification.badge = eep_count
+notification.sound = "default"
+notification.apns_collapse_id = goal.shortname
+
+notification.custom_payload = {
+  "userInfo" => {
+    "goalname" => goal.shortname
+  }
+}

Fixes #41

Summary

Open the goal corresponding to the tapped notification.

Validation

Testing by dropping a .apns file into the simulator.