Build

docker build -t myimage .

Run

docker run --name myimage --restart unless-stopped myimage

Start container and pass SLACK_API_TOKEN variable

docker run --name myimage -e SLACK_API_TOKEN=1234 --restart unless-stopped myimage

Run in background

docker run --name myimage --restart unless-stopped -d myimage

Kill & remove leftovers

docker kill myimage
docker rm myimage