def render
      buffer = ::Zip::OutputStream.write_buffer do |zip|
        render_package_relationships(zip)
        render_content_types(zip)
        render_app(zip)
        render_core(zip)
        render_custom(zip)
        render_fonts(zip)
        render_footer(zip)
        render_settings(zip)
        render_styles(zip)
        render_document(zip)
        render_relationships(zip)   # Must go here: Depends on document renderer
        render_media(zip)           # Must go here: Depends on document renderer
        render_numbering(zip)       # Must go here: Depends on document renderer
      end
    end
def render
      buffer = ::Zip::OutputStream.write_buffer do |zip|
        render_package_relationships(zip)
        render_content_types(zip)
        render_app(zip)
        render_core(zip)
        render_custom(zip)
        render_fonts(zip)
        render_footer(zip)
        render_settings(zip)
        render_styles(zip)
        render_document(zip)
        render_relationships(zip)   # Must go here: Depends on document renderer
        render_media(zip)           # Must go here: Depends on document renderer
        render_numbering(zip)       # Must go here: Depends on document renderer
      end
    end
============ RENDERING ===============================
 This method renders the word document instance into
 a string buffer. Order is important!