After downloading, extract the files into the directory where your website is located. Your directory should look something like this:
MyWebsite/
|--css/
| |--materialize.css
|
|--fonts/
| |--roboto/
|
|--js/
| |--materialize.js
|
|--index.html
<!DOCTYPE html>
<html>
<head>
<!--Import Google Icon Font-->
<link href="http://fonts.googleapis.com/icon?family=Material+Icons" rel="stylesheet">
<!--Import materialize.css-->
<link type="text/css" rel="stylesheet" href="css/materialize.min.css" media="screen,projection"/>
<!--Let browser know website is optimized for mobile-->
<meta name="viewport" content="width=device-width, initial-scale=1.0"/>
</head>
<body>
<!--Import jQuery before materialize.js-->
<script type="text/javascript" src="https://code.jquery.com/jquery-2.1.1.min.js"></script>
<script type="text/javascript" src="js/materialize.min.js"></script>
</body>
</html>
gem 'materialize-sass'
gem 'sass-rails', '~> 5.0'
bundle install
app/assets/stylesheets/application.scss:
@import "materialize";
app/assets/javascripts/application.js:
//= require jquery
//= require materialize-sprockets
application.html.erb
<%= stylesheet_link_tag 'https://fonts.googleapis.com/icon?family=Material+Icons' %>
<%= stylesheet_link_tag 'application', media: 'all' %>
<%= javascript_include_tag 'application' %>
<%= csrf_meta_tags %>
<meta name="viewport" content="width=device-width, initial-scale=1.0">