Add devise invitable gem and changed Devise from 3.0.0rc to 3.0.0
Add group_leader resource
remove group leader resource, add devise model for group leader
Remove all devise models, will start with general User model and create 1 additional  admin model for all types
Add Devise User and Devise Admin (god mode, group leader and lab manager booleans)
Run rake db:migrate
Remove devise admin model
Minor form change