Generally speaking, the absence of a license means that the default copyright laws apply. This means that you retain all rights to your source code and that nobody else may reproduce, distribute, or create derivative works from your work. This might not be what you intend.
Even if this is what you intend, if you publish your source code in a public repository on GitHub, you have accepted the Terms of Service which do allow other GitHub users some rights. Specifically, you allow others to view and fork your repository within the GitHub site.
If you want others to use, copy, modify, or contribute back to your project, we strongly encourage you to include an open source license.
License is not included, so nobody can use this code.
https://help.github.com/articles/open-source-licensing/
Quote:
Generally speaking, the absence of a license means that the default copyright laws apply. This means that you retain all rights to your source code and that nobody else may reproduce, distribute, or create derivative works from your work. This might not be what you intend.
Even if this is what you intend, if you publish your source code in a public repository on GitHub, you have accepted the Terms of Service which do allow other GitHub users some rights. Specifically, you allow others to view and fork your repository within the GitHub site.
If you want others to use, copy, modify, or contribute back to your project, we strongly encourage you to include an open source license.