Attempting to update metasploit to v4.8. Failing with ruby versions, etc

Heya,

So i'm trying to put together an updated package for metasploit, and running into a few issues with how to designate the ruby version required, etc.

It requires Ruby >= 1.9.2.

Decided I would create this pull request now to try and get some more expert advice/assistance on where I migh tbe going wrong/how I could go about it better.