Contribution
When submitting a pull request for the first time, you will need to agree to the contributor license agreement (for individuals or entities). To do this, in the pull request please create a file with a name like /contributors/{github_username}.md, and in the content of that file indicate your agreement. An example of what that file should contain can be seen in example agreement file.
(This method of CLA "signing" is borrowed from Medium's open source project.)