Answer by Mobiletainment for Git push existing repo to a new and different remote repo server?

I found a solution using set-url which is concise and fairly easy to understand:

1. create a new repo at Github
2. cd into the existing repository on your local machine (if you haven't cloned it yet, then do this first)
3. git remote set-url origin https://github.com/user/example.git
4. git push -u origin master