feat: Document presence indicator (#1114)

* Update websockets to allow joining document-based rooms

* dynamic websocket joining

* emit user.join/leave events when entering and exiting document rooms

* presence storage

* feat: frontend presence store

* lint

* UI updates

* First pass editing state

* refactoring

* Timeout per user/doc
lint

* Document data loading refactor to keep Socket mounted

* restore: Mark as viewed functionality
Add display of 'you' to collaborators

* fix: Socket/document remount when document slug changes due to title change

* Revert unneccessary package update

* Move editing ping interval to a shared constant

* fix: Flash of sidebar when loading page directly on editing mode

* separate document and revision loading

* add comments for socket events

* fix: Socket events getting bound multiple times on reconnect

* fix: Clear client side presence state on disconnect

* fix: Don't ignore server side error
Improved documentation

* More comments / why comments

* rename Socket -> SocketPresence

* fix: Handle redis is down
remove unneccessary join

* fix: PR feedback

app/scenes/Document/KeyedDocument.js

@@ -1,7 +1,7 @@
 // @flow
 import * as React from 'react';
 import { inject } from 'mobx-react';
-import Document from '.';
+import DataLoader from './components/DataLoader';
 
 class KeyedDocument extends React.Component<*> {
   componentWillUnmount() {
@@ -9,7 +9,15 @@ class KeyedDocument extends React.Component<*> {
   }
 
   render() {
-    return <Document key={this.props.location.pathname} {...this.props} />;
+    const { match } = this.props;
+
+    // the urlId portion of the url does not include the slugified title
+    // we only want to force a re-mount of the document component when the
+    // document changes, not when the title does so only this portion is used
+    // for the key.
+    const urlId = match.params.documentSlug.split('-')[1];
+
+    return <DataLoader key={urlId} {...this.props} />;
   }
 }