dep: update Rails and AR::Tenanted

Note that the query logs in this version of AR::Tenanted have changed,
to use standard Rails query log tags, which I have enabled.

Note that enabling Rails query log tags disables prepared
statements. I don't think turning off prepared statements will impact
our performance, but I'll verify that post-deploy (we have dashboards
for a reason).

config/application.rb

@@ -29,5 +29,9 @@ module Fizzy
 
     # use routes for error pages instead of static files
     config.exceptions_app = self.routes
+
+    # include the tenant in query logs
+    config.active_record.query_log_tags_enabled = true
+    config.active_record.query_log_tags = [ :tenant ]
   end
 end