.gitattributes to prune vendor dir with composer

[bbannon]

A blog at
https://www.reddit.com/r/PHP/comments/2jzp6k/i_dont_need_your_tests_in_my_production/?rdt=38070
suggests using a .gitattributes file to prevent composer from
including some folders in vendor dir.
For example:

/docs export-ignore
/tests export-ignore
/.gitattributes export-ignore
/.gitignore export-ignore
/.travis.yml export-ignore
/phpunit.xml export-ignore

Would that be easier than using makefile to cherry pick files to copy to pub after the fact?