When you first create a new repository in GitHub, you get a very handy drop down of Open Source Licenses options to add. This is really useful and saves you trying to find the standard copy somewhere.
If you don’t choose one when you create the repo, then there is a sneaky way to get that drop down back and easily add a standard license file later.
- At the root of the repository, create a new file and type in ‘license’ or ‘license.txt’ into the filename field and voila! you will see the ‘Want to use a template?’ drop down on the right.
- Select the license you prefer from the drop-down and the text will be copied to the new empty file.
- Commit the file.
After you have added the license you like this you will see a short cut link to it in the <>Code tab.
For full details see https://help.github.com/articles/adding-a-license-to-a-repository/
For help on choosing a license go to http://choosealicense.com/