Remove legacy code from Puma config.

config/puma/defaults.rb

@@ -23,13 +23,3 @@ on_restart do
   puts "Refreshing Gemfile"
   ENV["BUNDLE_GEMFILE"] = ""
 end
-
-before_fork do
-  ActiveRecord::Base.connection_pool.disconnect!
-end
-
-on_worker_boot do
-  ActiveSupport.on_load(:active_record) do
-    ActiveRecord::Base.establish_connection
-  end
-end