Add network config, add Ruby syntax HL in docs

I found that when using VirtualBox with a Vagrantfile without any declared network (the default host-only network was being used prior to this), that I got an error message requiring a network to be declared in the Vagrantfile.

Either public or private will work, also, DHCP is not required but it's a safe default :)
Merge pull request #30 from willmorgan/patch-1

Add network config, add Ruby syntax HL in docs