Merge commit from fork

* Streaming: Ensure disabled users cannot connect to streaming

* Streaming: Disconnect when the user is disabled

---------

Co-authored-by: Emelia Smith <ThisIsMissEm@users.noreply.github.com>

app/models/user.rb

@@ -180,6 +180,10 @@ class User < ApplicationRecord
 
   def disable!
     update!(disabled: true)
+
+    # This terminates all connections for the given account with the streaming
+    # server:
+    redis.publish("timeline:system:#{account.id}", Oj.dump(event: :kill))
   end
 
   def enable!