title: how do I set margins in Prawn in ruby?
body: <p>This is what I have so far, but I need to set margins:</p>
  
  <pre><code>def send_fax 
      contact = Contact.find_by_id(self.contact_id)
  
      pdf = Prawn::Document.new
      pdf.font "Times-Roman"
      pdf.move_down(20)
      pdf.text "ATTN: #{contact.first_name} #{contact.last_name}", :size =&gt; , :style =&gt; :bold
      pdf.text "RE: #{self.subject}"
      pdf.move_down(20)
  
      pdf.text "#{self.body}"
  
      OutboundMailer.deliver_fax_email(contact, self, pdf)
  
    end
  </code></pre>