added enable_new_users setting, default true
added form item and strong params
fixed .env comment
checked for user creation flag in controller
made UI registration elements dependent on flag
fixed Rails Admin weirdness
added some tests
updated Reservation#renew to log renewal
actually increment times_renewed
fixed nil errors
started using CanCanCan for ability
fixed specs
took out meaningless before_action
updated abilities to account for quick create modal
Merge pull request #1049 from YaleSTC/920_log_renewal

resolves #920
Merge pull request #1046 from YaleSTC/622_disable_new_users

resolves #622
Merge branch 'master' into 594_missed_reservations

Conflicts:
	app/controllers/app_configs_controller.rb
	db/schema.rb
removed delete_missed_reservations from app configs
updated strong params and rake task