item form now passes project_id through an hidden field
items can now be created from root or from a project (drop down doesn't appear in latter case)
adds 'completed' checkbox to item form
fixes item#update to put the test on the update_attributes() method and not save
adds team model, views, routes, controller
fixes render call in create method
adds user model, views, routes, controller (no auth)
create TeamMembership join table model, and has_many through assoc between users and teams