Changed string format to json; to allow for storage of extra parameters;...

Greetings,

I am using Mongoid and I am working on handling nested embedded documents, thus I actually need several keys to properly transverse the document to find the data I am looking for, much in this manner.

User(id)->Profile(id)->Picture(id).   

I was looking at the code and I thought that a JSON formatted string would allow me to store several keys at the same time for embedded documents and moving into the future, extra information such as the database to connect to, and potentially other information would make the id more future proof.

This code doesn't do all of that work; but I wanted to see how you felt about it before committing more work.  All the tests pass.

Regards,

-daniel