APNS Subscription Service (Message Grouping)

[rjcarter]

So i have a crack at setting up message groups. Basically I want to
send messages to sub groups of users and not the whole install base.
My solution that I am testing is as follows.

1. I created a list of alerts types using a bit mask scheme.
alert type one 1
alert type two 2
alert type three 4
etc ...

2. I modified the register task to add the alert type field.

3. I added a column on the apns_devices table to hold the alert type
information and made it a TINYINT.

4. I created a settings in the setttings bundle of my app so users can
choose which alert types they want to receive.

5. Modified my alert script to query the database on active and alert
types to produce a list a devices to send an alert.

This was my approach at minimally disrupting the Easy APNS codebase
and database. I am testing it right now and seems to be working.

Any feedback is welcomed and maybe this is some that can be added
later.