Adding Sidekiq for background processing (firstly just of mailers)

config/application.rb

@@ -28,6 +28,8 @@ module Mastodon
     config.paths.add File.join('app', 'api'), glob: File.join('**', '*.rb')
     config.autoload_paths += Dir[Rails.root.join('app', 'api', '*')]
 
+    config.active_job.queue_adapter = :sidekiq
+
     config.to_prepare do
       Doorkeeper::ApplicationsController.layout           'dashboard'
       Doorkeeper::AuthorizedApplicationsController.layout 'dashboard'

config/initializers/sidekiq.rb

@@ -0,0 +1,11 @@
+redis_conn = proc {
+  $redis.dup
+}
+
+Sidekiq.configure_server do |config|
+  config.redis = ConnectionPool.new(size: 5, &redis_conn)
+end
+
+Sidekiq.configure_client do |config|
+  config.redis = ConnectionPool.new(size: 25, &redis_conn)
+end

config/routes.rb

@@ -1,4 +1,10 @@
+require 'sidekiq/web'
+
 Rails.application.routes.draw do
+  authenticate :user do
+    mount Sidekiq::Web => '/sidekiq'
+  end
+
   use_doorkeeper do
     controllers applications: 'oauth/applications'
   end