//TODO


 - background job for re-delivery
 - POST::/messages
 - https://firebase.google.com/docs/cloud-messaging/send-message#rest
 - List subscriptions on all owned channels (RESTful?)
 - deploy
 - Dockerfile
 - php in html
 - full-text-search: https://www.sqlite.org/fts5.html#contentless_tables
 - route to re-create keys 
 - ack/read deliveries && return ack-count
 - compat methods should bind body as form-data