Use package bundler for frontend

[sanemat]

sample_accounts_api/app/views/layouts/application.html.erb

Lines 5 to 8 in 5fc51e5

	<link rel="stylesheet"
	href="https://cdnjs.cloudflare.com/ajax/libs/bulma/0.7.1/css/bulma.min.css"
	integrity="sha256-zIG416V1ynj3Wgju/scU80KAEWOsO5rRLfVyRDuOv7Q="
	crossorigin="anonymous" />

😓