How to add or import github repositories to gitlab

I have hosted a gitlab pod in kubernetes cluster —
I need help in adding or importing bitbucket repos into gitlab not by dashboard or UI but by gitlab pod .I can see from pod after executing kubectl exec -it bash ,with this path → /var/opt/gitlab/git-data/repositories/oraganization # list of repositories.How can I add repositories form another github or bitbucket server here or some where form the pod itself so that I can see it in dashboard ?