app/views/layouts/login.html.erb
<!DOCTYPE html>
<html>
<head>
<title>Sign In</title>
<!-- Fonts -->
<link rel="stylesheet" type="text/css" href="//fonts.googleapis.com/css?family=Open+Sans" />
<link rel="stylesheet" type="text/css" href="//fonts.googleapis.com/css?family=Forum" />
<%= stylesheet_link_tag 'login', media: 'all' %>
<%= csrf_meta_tags %>
</head>
<body>
<!-- This yield will fill in the users/sign_in view -->
<%= yield %>
</body>
<%= javascript_include_tag 'application' %>
</html>