<!DOCTYPE html>
<html>
  <head>
    <title>Ezmeals</title>
    <%= csrf_meta_tags %>

    <%= stylesheet_link_tag    'application', media: 'all' %>
    <%= javascript_include_tag 'application' %>
  </head>

  <body>
    <%= yield %>
  </body>
</html>

<!DOCTYPE html>
<html>
  <head>
    <title>Ezmeals</title>

    <!-- Latest compiled and minified CSS -->
		<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous">

		<!-- Optional theme -->
		<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap-theme.min.css" integrity="sha384-rHyoN1iRsVXV4nD0JutlnGaslCJuC7uwjduW9SVrLvRYooPp2bWYgmgJQIXwl/Sp" crossorigin="anonymous">

		<!-- Latest compiled and minified JavaScript -->
		<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js" integrity="sha384-Tc5IQib027qvyjSMfHjOMaLkfuWVxZxUPnCJA7l2mCWNIpG9mGCD8wGNIcPD7Txa" crossorigin="anonymous"></script>
    
    <%= csrf_meta_tags %>

    <%= stylesheet_link_tag    'application', media: 'all' %>
    <%= javascript_include_tag 'application' %>
  </head>

  <body>
  	<nav class="navbar navbar-default">
  		<div class="container-fluid">
  			<div class="navbar-header">
  				<a href="/" class="navbar-brand">Home</a>
  			</div>
  			<div class="collapse navbar-collapse">
  				<ul class="nav navbar-nav">
  					<% if current_user %>
  					<li><%= link_to(current_user.name, user_path(current_user)) %></li>
						<li><form class="navbar-form" action="/logout" method="get">
							<input class="btn btn-link" type="submit" value="Logout">
						</form></li>
  					<% else %>
  					<li><%= link_to('Login', '/login', method: :get) %></li>
  					<li><%= link_to("Register", '/users/new') %></li>
  					<% end %>
  				</ul>
  			</div>
  		</div>
  		
  	</nav>
    <%= yield %>
  </body>
</html>

Add nav bar and associated elements; add bootstrap CDN
Add nav bar and associated elements; add bootstrap CDN
