Set access_token in envfile. You should be able to get it from creating a new Twitter app.
curl -X POST "https://api.twitter.com/oauth2/token" -d "grant_type=client_credentials" -u consumerKey:consumerSecret
echo 'access_token=secret' > envfile
docker run -d --restart=unless-stopped -v /mnt/raid1/greptweet/:/srv/http/u --name greptweet --env-file envfile -p 8888:80 hendry/greptweet
Backing it up:
docker cp greptweet:/srv/http/u/ /tmp/backup