implement alternative match-making approach with Lua scripts in Redis

main-server/app/jobs/matchmaking_sweep_job.rb

@@ -0,0 +1,10 @@
+# Periodically re-checks the matchmaking queue: pairs players whose rating
+# tolerance has widened enough, expires timed-out waiters and requeues
+# players stuck in the pending state. Scheduled via config/recurring.yml.
+class MatchmakingSweepJob < ApplicationJob
+  queue_as :default
+
+  def perform
+    MatchmakingService.sweep
+  end
+end