GitLab includes git repository management, code reviews, an issue tracking, wiki’s and much more. GitLab InstantApp comes with GitLab CI, an easy to use continuous integration and deployment tool. You can discuss issues and plan milestones together. Do code reviews and make line comments. Mention your colleagues anywhere. View activity streams of projects or people.
GitLab has integrations for tons of tools such as Slack, Hipchat, LDAP, JIRA, Jenkins, many types of hooks and a complete API.