Simplified dockerfile

[rothgar]

Changed the container so it is easier to manage going forward.

• Based on official ruby image instead of ubuntu 13.10 (EOL)
• Installed latest nodejs and npm from nodesource
• run web interface under hubot user for security and fix problem creating new bots using root permissions

Dockerfile builds and works on my system with db and storage containers. I'm using Docker 1.4.1

[coveralls]

Coverage remained the same at 85.48% when pulling ec9c554 on rothgar:ruby-container into 4414135 on spajus:master.

[rothgar]

I forgot my .gitignore was ignoring the Gemfile.lock which is needed for the ruby image.

[coveralls]

Coverage remained the same at 85.48% when pulling ee3e08e on rothgar:ruby-container into 4414135 on spajus:master.

[spajus]

Thank you!