fredmontet

Go to Bitbucket and create a new repository (its better to have an empty repo)
    git clone git@bitbucket.org:abc/myforkedrepo.git
    cd myforkedrepo

Now add Github repo as a new remote in Bitbucket called "sync"
    git remote add sync git@github.com:def/originalrepo.git

Verify what are the remotes currently being setup for "myforkedrepo". This following command should show "fetch" and "push" for two remotes i.e. "origin" and "sync"
    git remote -v