Feature/rails 41

@sakhtermdsol @rbuenviaje-mdsol - I'm open this PR up on the imedidata branch, since that the branch hippocrates uses.  (do we have a canonical branch with a tag?).  

In any case, this PR adds ActiveRecord 4 support to session updates, since the current version uses a deleted API.  We needed this for hippocrates, and rails 4.1.x app.

Let me know if I need to open this on a different branch.