app/views/layouts/application.html.erb
<!DOCTYPE html>
<html>
<head>
<title>Dontfile<%= content_for?(:title) ? ' | ' + yield(:title) : ''%></title>
<meta name="viewport" content="width=device-width, initial-scale=1">
<%= csrf_meta_tags %>
<%= stylesheet_link_tag 'application', media: 'all', 'data-turbolinks-track': 'reload' %>
<%= javascript_include_tag 'application', 'data-turbolinks-track': 'reload' %>
<%= favicon_link_tag 'favicon.ico' %>
<link rel="stylesheet" href="https://use.fontawesome.com/releases/v5.0.12/css/all.css" integrity="sha384-G0fIWCsCzJIMAVNQPfjH08cyYaUtMwjJwqiRKxxE/rx96Uroj1BtIQ6MLJuheaO9" crossorigin="anonymous">
</head>
<body>
<%= yield %>
</body>
</html>