app/views/layouts/application.html.erb
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title><%= full_title(yield(:title)) %></title>
<%= stylesheet_pack_tag "application" %>
<%= javascript_pack_tag 'application' %>
<%= csrf_meta_tags %>
</head>
<body>
<%= render 'layouts/header' %>
<main class="container">
<% flash.each do |key, value| %>
<div class="alert alert-<%= key %>"><%= value %></div>
<% end %>
<%= yield %>
<%= render 'layouts/footer' %>
<%= debug(params) if Rails.env.development? %>
</main>
</body>
</html>