$ dockmux $(docker ps -q)

dockmux

#!/bin/bash

if [[ -e ~/.dockmux/$1 ]]; then
        CONTAINERS=$(cat ~/.dockmux/$1)
        SESSION_NAME=$1
else
        CONTAINERS="$@"
        SESSION_NAME=dockmux
fi

tmux new-session -d -s $SESSION_NAME
shift
for CONTAINER in $CONTAINERS; do
  tmux new-window -n `docker inspect -f ''{{.Config.Hostname}}'' $CONTAINER` "docker exec -i -t $CONTAINER /bin/bash"
done
tmux kill-window -t 0
tmux select-window -t 1
tmux attach -t $SESSION_NAME

Credits to http://github.com/wbond/mtmux.git