Reusable Travis CI setup

Thanks for commitlint and for the CI setup tutorial! I like the pre-prepared shell script, which counts with all the possibilities which can happen when using GitHub and Travis CI, but currently I can only use it as part of my project by copy-pasting from the docs.

Since it’s not two lines, but a bunch of them, many if/elses included, I’m wondering whether it would make sense to turn it into a separate package. I want to install commitlint on multiple repositories and I believe being able to do just sth like npm i commitlint-travis --save-dev instead of copy-pasting the script would make the maintenance of the repos easier as well as doing any updates if e.g. Travis CI or GitHub make any changes and the flow breaks.

What do you think? I’m happy to help.

[felixfbecker]

@honzajavorek what if the PR base is not master?

[honzajavorek]

So far I came up with following simplification: https://github.com/apiaryio/dredd-transactions/pull/116

#!/bin/bash
set -e
git remote set-branches origin master
git fetch --unshallow --quiet
git checkout master --quiet
git checkout - --quiet
./node_modules/.bin/commitlint --from=master --to="$TRAVIS_COMMIT"

I’m not sure whether this can be further simplified, but it seems to work for all the scenarios when I played with it.