Use mongoid connection instead of Mongo gem

mongoid version > 3.0.0 use configure below:
http://mongoid.org/en/mongoid/docs/installation.html#configuration
I use stackoverflow answer:
http://stackoverflow.com/questions/12511699/mongoid-uninitialized-constant-mongo-nameerror
Merge pull request #203 from sanemat/feature/cucumer-mongoid

Use mongoid connection instead of Mongo gem