add an event when a question is assigned and sync to Cloudant - issue #106

[glynnbird]

When a question is assigned, a new document is added to the events PouchDB database, like so:

{
  "_id": "53f6bd4f-849e-46d8-b7e5-d41923dc22fe",
  "_rev": "1-4ed835465fa844baa1ee5a5680f4f742",
  "type": "assigned",
  "assigned_by": "U7844223OL",
  "assigned_by_name": "stevie.smith",
  "assigned_at": "2018-02-08T08:53:58.518Z",
  "assigned_to": "U0Z2VN3EU",
  "assigned_to_name": "glynn.bird",
  "notified": false
}

PouchDB is then instructed to replicate to the remote Cloudant events database as a one-off operation.

To test:

• make sure there is an events database on the Cloudant side see issue #108
• open sodashboard from this branch
• assign a ticket to someone
• check that local events database contains some data - in the web developer console eventsdb.allDocs({include_docs:true}).then(console.log)
• look for log message indicating that replication completed - events sync complete {ok: true, start_time: Thu Feb 08 2018 08:53:58 GMT+0000 (GMT), docs_read: 1, docs_written: 1, doc_write_failures: 0, …}
• check the Cloudant side events database to see if the document arrived

[glynnbird]

sure. That should be easy enough