Added condition for counter

Added 2 models for specs
changed ruby version to 2.1.0 and mongoid version to 4.0.0
Added specs for embedded document.
Specified mongoid ver as 4.0
Code modified to run for 2.x to 4.x mongoid versions.
Added code to find mongoid version.
Fixing .travis.yml merge conflict.
Merge pull request #13 from jah2488/Sameer-Tilak-master

Condition added for counter cache