These instructions show you how to change the config.json file for a Docker Mattermost Preview.
a- As root (or if you enabled non root users to manipulate docker), let’s open a shell in the docker container
docker exec -ti mattermost-preview /bin/bash
b. Update the APT db on the docker instance and install vim (needed to edit the file)
apt update
apt install vim
c. Change config_docker.json as needed
cd /mm/mattermost/config
vim config_docker.json
d. Restart the docker container
docker restart mattermost-preview
