Add uuid to usage ping

lib/gitlab/usage_data.rb

 module Gitlab
   class UsageData
+    include Gitlab::CurrentSettings
+
     class << self
       def data(force_refresh: false)
         Rails.cache.fetch('usage_data', force: force_refresh, expires_in: 2.weeks) { uncached_data }
@@ -51,7 +53,8 @@ module Gitlab
       end
 
       def license_usage_data
-        usage_data = { version: Gitlab::VERSION,
+        usage_data = { uuid: current_application_settings.uuid,
+                       version: Gitlab::VERSION,
                        active_user_count: User.active.count,
                        mattermost_enabled: Gitlab.config.mattermost.enabled }
 

spec/lib/gitlab/usage_data_spec.rb

@@ -22,6 +22,7 @@ describe Gitlab::UsageData do
         recorded_at
         version
         mattermost_enabled
+        uuid
       ))
     end
 
@@ -72,6 +73,7 @@ describe Gitlab::UsageData do
     it "gathers license data" do
       license = ::License.current
 
+      expect(subject[:uuid]).to eq(current_application_settings.uuid)
       expect(subject[:license_md5]).to eq(Digest::MD5.hexdigest(license.data))
       expect(subject[:version]).to eq(Gitlab::VERSION)
       expect(subject[:licensee]).to eq(license.licensee)