Port error because marker based visual loc ex

[dduro2020]

If you kill the docker inside the marker based visual loc exercise, it does not clean up the processes correctly and causes the docker to not work when relaunching the docker with the developers script.

[dduro2020]

To fix this error manually. First find the stopped dockers and delete them by hand:

docker ps -a

Copy the ids and kill them:

docker rm <id>