def add_attachment(attachment, name = '')
      # Is it a file object or a string (url)?
      if attachment.respond_to?(:path) && attachment.respond_to?(:read)
        client.post("/cards/#{id}/attachments", {
            file: attachment,
            name: name
          })
      else
        client.post("/cards/#{id}/attachments", {
            url: attachment,
            name: name
          })
      end
    end
def add_attachment(attachment, name = '')
      # Is it a file object or a string (url)?
      if attachment.respond_to?(:path) && attachment.respond_to?(:read)
        client.post("/cards/#{id}/attachments", {
            file: attachment,
            name: name
          })
      else
        client.post("/cards/#{id}/attachments", {
            url: attachment,
            name: name
          })
      end
    end
Add an attachment to this card