add rails_admin/device
add cancan
 add rails admin and cancan
add user admin seed
fix readme
Merge branch 'feature/add_rails_admin' into staging

Conflicts:
	Gemfile
	Gemfile.lock
	app/assets/stylesheets/application.css
	app/views/layouts/application.html.haml
	config/routes.rb
	db/schema.rb