Update installation instructions for docker
Update installation instructions for docker

sandrokeil/proophessor-do,prooph/proophessor-do,sandrokeil/proophessor-do,prooph/proophessor-do,prooph/proophessor-do,prooph/proophessor-do,sandrokeil/proophessor-do,bgaleotti/proophessor-do,bgaleotti/proophessor-do,bgaleotti/proophessor-do,sandrokeil/proophessor-do,bgaleotti/proophessor-do