Redmine Git Mirror plugin 
Adds ability to clone and fetch remote git repositories to redmine.
Key Features
- Easy install (just clone to redmine plugins folder)
- Webhooks integration (gitlab and custom)
- Works well with enabled autofetch changesets setting and in mix with other scm types
- Automatic deletes unreachable commits
Install
cd [redmine-root]/plugins
git clone https://github.com/linniksa/redmine_git_mirror
Restart redmine, and enable Git Mirror scm type at redmine.site/settings?tab=repositories
Accessing private repositories
At this moment only ssh access with redmine user ssh key is supported.
Fetching changes
This plugin supports 2 ways of fetching changes, via cronjob or via hooks. You can use only one or both of them together.
Cronjob
Run ./bin/rails runner "Repository::GitMirror.fetch", for example:
5,20,35,50 * * * * cd /usr/src/redmine && ./bin/rails runner "Repository::GitMirror.fetch" -e production >> log/cron_rake.log 2>&1
Hooks
Hooks is preferred way because you can immediately see changes of you repository.
GitLab hooks
You can setup per-project or system wide hook, for both variants use redmine.site/sys/git_mirror/gitlab as URL
For system wide setup
Go to gitlab.site/admin/hooks, and select only Repository update events trigger.
For per-project setup
Go to gitlab.site/user/project/settings/integrations, and select only Push and Tags events
GitHub hooks
You can setup per-project or group wide hook, for both variants
use redmine.site/sys/git_mirror/github as Payload URL and Just the push event option.
Don't worry about Content type both application/json and application/x-www-form-urlencoded are supported.