remove person.csv and replace with people.csv [address #191]
refactored group creation specs
Update nokogiri.
Use FileImage concern for Attachment model too.

Might fix #193
Rewrite and improve test coverage for GroupsController.
Split up large GroupsController#index method.
Simplify member_of logic a bit.
Update remaining old-style finders [fixes #185]
Refresh the page when adding first group member [fixes #148]
Fix broken spec after change to Person#member_of? method.
Merge branch 'master' of https://github.com/churchio/onebody