add puma dependency to debian/control, add puma systemd service, update gitlab service with puma

debian/control

@@ -163,14 +163,10 @@ Depends: ${shlibs:Depends}, ${misc:Depends},
  ruby-diffy (>= 3.3~),
  ruby-diff-match-patch (>= 0.1~),
 # Application server
-# The 2.0.6 version of rack requires monkeypatch to be present in
-# `config.ru`. This can be removed once a new update for Rack
-# is available that contains https://github.com/rack/rack/pull/1201
  ruby-rack (>= 2.1~),
  ruby-rack-timeout (>= 0.5.1~),
- unicorn (>= 5.5~),
-   ruby-kgio (>= 2.11.2~),
- ruby-unicorn-worker-killer (>= 0.4.4-2~),
+ puma (>= 4.0~),
+ ruby-puma-worker-killer,
 # State machine
  ruby-state-machines-activerecord (>= 0.6~),
    ruby-state-machines-activemodel (>= 0.7.1~),

debian/gitlab.gitlab-puma.service

@@ -0,0 +1,21 @@
+[Unit]
+Description=GitLab Puma Server
+PartOf=gitlab.target
+Requires=redis-server.service
+Wants=postgresql.service
+After=redis-server.service postgresql.service
+PartOf=gitlab.service
+ReloadPropagatedFrom=gitlab.service
+
+[Service]
+Type=simple
+WorkingDirectory=/usr/share/gitlab
+EnvironmentFile=/etc/gitlab/gitlab-debian.conf
+EnvironmentFile=-/etc/default/gitlab
+SyslogIdentifier=gitlab-unicorn
+ExecStart=/usr/bin/bundle exec puma -C config/unicorn.rb -e $RAILS_ENV
+ExecReload=/bin/kill -USR2 $MAINPID
+Restart=on-abnormal
+
+[Install]
+WantedBy=gitlab.target

debian/gitlab.service

@@ -1,6 +1,6 @@
 [Unit]
 Description=GitLab Services
-BindsTo=gitlab-unicorn.service gitlab-sidekiq.service gitlab-mailroom.service gitlab-workhorse.service
+BindsTo=gitlab-puma.service gitlab-sidekiq.service gitlab-mailroom.service gitlab-workhorse.service
 After=gitlab-unicorn.service gitlab-sidekiq.service gitlab-mailroom.service gitlab-workhorse.service
 
 [Service]