Add a combined update doc from 5.1 to 6.0
Report application status through init exit code
Refer to disclosure policy in CONTRIBUTING.md
Merge branch 'init_exit_status' of /home/git/repositories/gitlab/gitlabhq
Merge branch 'security_vulnerabilities' of /home/git/repositories/gitlab/gitlabhq
Merge branch '51-to-60-update' of /home/git/repositories/gitlab/gitlabhq
API: set gitlab-ci service for project
Merge branch 'api/gitlab-ci' of /home/git/repositories/gitlab/gitlabhq
gitlab-ci service api: clean values instead of destroy
Merge pull request #117 from gitlabhq/master

Update