Sidekiq API doesn't include `post_receive` and `email_receiver` queues
gitlab-monitor isn't plotting these because the Sidekiq set doesn't include them:
> smembers resque:gitlab:queues
1) "project_web_hook"
2) "merge"
3) "pipeline"
4) "delete_user"
5) "update_merge_requests"
6) "cronjob"
7) "system_hook"
8) "project_destroy"
9) "mailer"
10) "repository_import"
11) "expire_build_instance_artifacts"
12) "gitlab_shell"
13) "project_service"
14) "git_garbage_collect"
15) "default"
16) "mailers"
17) "project_cache"
18) "group_destroy"
19) "project_update_repository_storage"
20) "archive_repo"
21) "emails_on_push"
22) "elasticsearch"
23) "repository_fork"
24) "new_note"
25) "pages"
26) "project_export"
27) "build"
28) "irker"