if you try to push back to git on circle CI, you will get below error:
The reason is the default ssh key circle ci created on github is a read-only key. for more information: https://circleci.com/docs/adding-read-write-deployment-key/
There are two ways to enable this.
1. just follow above link to create a new key and put into github and circle ci.
2. you can put your personal key into circle ci (the current circle ci user and github user) and then you should let github to use your github username to push.
Before this you should be see another button here asking you to give permission. just click it.
after that you should run this script on your ci:
git config user.email "firstname.lastname@example.org" git config user.name "xxxxx"
above email@example.com should be your github account email.