added volumes for gitblit-ssh-daemon
Merge branch 'master' of http://git.home.lan/git/docker/gitblit-data
replaced command "sudo docker.io" with "docker" to clarify examples
Updating to gitblit 1.5.1. Adding shasum checking during build. Adding ssh port config.
Adding shasum checking during build
changed to more closely mirror docker-gitblit repo
Merging changes before pushing new changes for GitBlit 1.5.1.