should update docs how to use teracy/travis along with teracy/ubuntu for local CI testing

[hoatle]

• make sure this works:

vagrant@teracy:~/workspace/docker-files$ docker run --rm -v $(pwd):/tmp -w /tmp hoatle/travis compile > build.sh
detected repository as teracyhq/docker-files
env.matrix key is ignored
vagrant@teracy:~/workspace/docker-files$ docker run --rm -it -v /var/run/docker.sock:/var/run/docker.sock -v $(pwd):/$(pwd) -w $(pwd) teracy/ubuntu:16.04-dind-17.06.0-ce bash
root@68388adc3f9e:/home/vagrant/workspace/docker-files# bash build.sh 

it should run the same as on travis-ci (with some exceptions mentioned by travis-build)

And this should help us to update the section Local CI Testing with a real project at http://blog.teracy.com/2017/09/11/how-to-use-docker-in-docker-dind-and-docker-outside-of-docker-dood-for-local-ci-testing/