Simple way to do it  :

git branch -m old_branch new_branch         # Rename branch locally    
git push origin :old_branch                 # Delete the old branch    
git push --set-upstream origin new_branch   # Push the new branch, set local branch to track the new remote

For more, see this.

A simple way to do it:

git branch -m old_branch new_branch         # Rename branch locally
git push origin :old_branch                 # Delete the old branch
git push --set-upstream origin new_branch   # Push the new branch, set local branch to track the new remote

For more, see this.