status updates for Google Calendar events

Saving a calendar:
- user authenticates with google ( https://www.firebase.com/docs/web/guide/login/google.html )
- selects calendar from list of calendars ( https://developers.google.com/google-apps/calendar/v3/reference/calendarList/list )
- store calendar ID in FB
- register webhooks for that calendar
"Master" task runs daily as well as when the server restarts:
- pulls all events for the day from all calendars ( https://developers.google.com/identity/protocols/OAuth2WebServer#overview, https://developers.google.com/google-apps/calendar/v3/reference/events/list )
- this will be with FB.on() so that newly added/removed cals are updated
- NB: we may need to authenticate the user from our own server and not via FB in order to obtain "offline" access
- schedules status update tasks ("Worker") for the events ( https://www.npmjs.com/package/node-schedule )
- maintains a list of Workers
- registers webhooks for that days' events
"Worker" tasks run when an event is thought to start
- checks the calendar to make sure the event is still there
- posts a status update
Webhook hit when any event in a subscribed calendar has changed
- if event has a scheduled Worker task, update that task as necessary
Removing a calendar:
- user must be authenticated with google
- selects calendar from list of saved calendars
- removes calendar meta from FB

Phasedio / webapp