apt-get update -y under line:3 of Dockerfile

[ajeetraina]

Couple of time I have used Dockerfile to build the gource image and I faced issue with initial package installation. It would be better to add -y with apt-get update.

[taivokasper]

I have fixed this issue, issue where you might have had a container where 'apt-get update' was already done a while back and fixed the ubuntu version.

Also published it to Docker Hub.