title: How to use custom font with Weasyprint for non-ascii characters
body: <p>I have some strings in Japanese that need to be converted to PDF using weasyprint library, for now the japanese characters appear as boxes so I guess it's a matter of fonts, my problem is the code is working perfectly on my local OS, but on Heroku its showing boxes instead, how can I install and use custom font for weasyprint specifically when I don't have access to the system (in my case Heroku)</p>
  
  <p>below is the code I have</p>
  
  <pre><code>from weasyprint import HTML, CSS
  from weasyprint.fonts import FontConfiguration
  
  font_config = FontConfiguration()
  html = HTML(string='&lt;h1&gt;Title here 自家製フォント工房&lt;/h1&gt;')
  css = CSS(string='''''', font_config=font_config)
  
  html.write_pdf(
      'report.pdf', stylesheets=[css],
      font_config=font_config)
  </code></pre>