Here are the issues
* webapp was built with `NODE_ENV=production` but started with
`NODE_ENV=development`
* using the provided `docker-compose.travis.yml` the command `yarn run
start` would look in the wrong folder
* removed duplicate environment definition
NuxtJS wants to write into .nuxt. If the docker container writes into
.nuxt it will have the file permissions of the docker container user
even on the host system. So on the host system you cannot remove the
folder .nuxt anymore. This gets in the way of running NuxtJS on the host
system.
