def generate_content
      @pdf = Prawn::Document.new(
        info: self.metadata,
        top_margin: @format[:header_size] + @format[:top_margin],
        bottom_margin: @format[:footer_size] + @format[:bottom_margin]
      )
      add_page_body
      add_page_header
      add_page_footer
      add_page_numbering
    end
def generate_content
      @pdf = Prawn::Document.new(
        info: self.metadata,
        top_margin: @format[:header_size] + @format[:top_margin],
        bottom_margin: @format[:footer_size] + @format[:bottom_margin]
      )
      add_page_body
      add_page_header
      add_page_footer
      add_page_numbering
    end
Generate the document content
 by adding body, header, footer and
 page numbering