Now we have 2 different Zulip apps out there, and they are signed with
two certs: Zulip and Dropbox. The Dropbox-signed apps are going to need
to be sent APNS notifications from the appropriate APNS connection
(imported from commit 6db50c5811847db4f08e5c997c7bbb4b46cfc462)
While we're at it, lets comment up the function so I know what this is
doing next time :)
(imported from commit e745be75fcd6dbce9997e1d73464619fc8b73996)
This replaces the AppleDeviceToken table with a generic
PushDeviceToken with a `kind` field to make it easier to add functionality
like per-device/per-stream settings that share code between Android and
iOS devices.
The schema must continue to work on prod with the old table name, so we
add the new table in parallel and can drop the old table once this code
hits prod and any necessary data is copied.
(imported from commit 0209a7013f2850ac6311f23c3d6f92c65ffd19e3)