Travis-CI is automatically rebuilding and testing your code every time you push your modifications on GitHub. The coverage option let you test your code coverage locally. Now, if you want to get your code coverage with every Travis-CI build, Coveralls_io is the right tool for you.

This option add the relevant files to let your package use Coveralls_io, a web service that will automatically check the test coverage of your code. This option install local configuration files but you still need to register by hand. Have a look at the Coveralls Documentation or Register on tutorial for more information:

(dvlpt)$ pmg add coveralls
(dvlpt)$ pmg rg

$ git add --all
$ git commit -m"added coveralls support"
$ git push