This post is older than a year. Consider some information might not be accurate anymore.
If you access the git repository via HTTPS you have to provide each time authentication data. Switching to SSH is more convenient and secure. After adding your public SSH key to the repository in GitHub (or any other) you can access the repository with SSH. To switch your local git repository:
# show current remote urls git remote -v # switch remote git remote set-url origin firstname.lastname@example.org/user/repository.git # check again git remote -v
Replace user and repository and you are done. You may consider that other providers like Atlassian Stash or Bitbucket have another syntax.
# Bitbucket example with user git remote set-url origin ssh://email@example.com:user/repository.git # Atlassian Stash example with default ssh port git remote set-url origin ssh://git@stashhost:7999/repository.git