TypeError: undefined is not a function

Hi,

When I use SCSS, I can see my home page, but when I try Stylus, I get the following error:

```
ExecJS::ProgramError
TypeError: undefined is not a function
```

On this line of my application.html.erb file:

```
  <%= stylesheet_link_tag    'application', media: 'all', 'data-turbolinks-track' => true %>
```

Do you have any clue?
