Add RoomTile online indicator to DMs

res/css/views/rooms/_RoomTile.scss

@@ -1,5 +1,6 @@
 /*
 Copyright 2015, 2016 OpenMarket Ltd
+Copyright 2019 The Matrix.org Foundation C.I.C.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -61,6 +62,14 @@ limitations under the License.
     min-width: 0;
 }
 
+.mx_RoomTile_online_dot {
+    border-radius: 50%;
+    background-color: $accent-color;
+    height: 5px;
+    width: 5px;
+    display: inline-block;
+}
+
 .mx_RoomTile_subtext {
     display: inline-block;
     font-size: 11px;