fixed dockerbuild
fixed dockerbuild

since i did not know about go-lang's feature
"import from github" my previous dockerfile
did not actually build the current revision,
instead it went to github and pulled it from there.

mailslurper/mailslurper,mailslurper/mailslurper,mailslurper/mailslurper,mailslurper/mailslurper,mailslurper/mailslurper