Only execute GitlabCiService for push events.

app/models/project_services/gitlab_ci_service.rb

@@ -22,8 +22,6 @@ class GitlabCiService < CiService
   validates :project_url, presence: true, if: :activated?
   validates :token, presence: true, if: :activated?
 
-  delegate :execute, to: :service_hook, prefix: nil
-
   after_save :compose_service_hook, if: :activated?
 
   def compose_service_hook
@@ -32,6 +30,13 @@ class GitlabCiService < CiService
     hook.save
   end
 
+  def execute(data)
+    object_kind = data[:object_kind]
+    return unless object_kind == "push"
+
+    service_hook.execute(data)
+  end
+
   def commit_status_path(sha)
     project_url + "/commits/#{sha}/status.json?token=#{token}"
   end