Websocket Support (#937)

* Atom / RSS meta link

* Spike

* Feeling good about this spike now

* Remove document.collection

* Remove koa.ctx from all presenters to make them portable outside requests

* Remove full serialized model from events
Move events.add to controllers for now, will eventually be in commands

* collections.create event
parentDocument -> parentDocumentId

* Fix up deprecated tests

* Fixed: Doc creation

* documents.move

* Handle collection deleted

* 💚

* Authorize room join requests

* Move starred data structure
Account for documents with no context on sockets

* Add socket.io-redis

* Add WEBSOCKETS_ENABLED env variable to disable websockets entirely for self hosted
New installations will default to true, existing installations to false

* 💚 No need for promise response here

* Reload notice

server/presenters/user.test.js

@@ -1,9 +1,8 @@
 /* eslint-disable flowtype/require-valid-file-annotation */
 import presentUser from './user';
-import ctx from '../../__mocks__/ctx';
 
 it('presents a user', async () => {
-  const user = await presentUser(ctx, {
+  const user = await presentUser({
     id: '123',
     name: 'Test User',
     username: 'testuser',
@@ -16,7 +15,7 @@ it('presents a user', async () => {
 });
 
 it('presents a user without slack data', async () => {
-  const user = await presentUser(ctx, {
+  const user = await presentUser({
     id: '123',
     name: 'Test User',
     username: 'testuser',