message: add PDF and posting attachments examples to node readme
diff: @@ -119,7 +119,7 @@ The `tokenSet` is what you should store in your database. That object is what yo
  Populate the XeroClient's active tenant data.
  -For most integrations you will want to display the org name and use additional metadata about the connected org. The `/connections` endpoint does not currently serialize all org metadata so requires developers to make an additional calls for each org that your user connects to get information like default currency.
  +For most integrations you will want to display the org name and use additional metadata about the connected org. The `/connections` endpoint does not currently serialize all org metadata so requires developers to make an additional call for each org your user connects to get information like default currency.
  Calling `await xero.updateTenants()` will query the /connections endpoint and store the resulting information on the client. It has an optional parameter named `fullOrgDetails` that defaults to `true`. If you do not pass `false` to this function you will need to have the `accounting.settings` scope on your token as the `/organisation` endpoint that is called, requires it.
  @@ -260,6 +260,27 @@ const invoices = {
  };
  const createdInvoice = await xero.accountingApi.createInvoices(activeTenantId, invoices)
  +
  +---
  +
  +// getting files as PDF
  +const getAsPdf = await xero.accountingApi.getPurchaseOrderAsPdf(
  + req.session.activeTenant.tenantId,
  + getPurchaseOrdersResponse.body.purchaseOrders[0].purchaseOrderID,
  + { headers: { accept: 'application/pdf' } }
  +)
  +
  +// CREATE ATTACHMENT
  +const filename = "xero-dev.png";
  +const pathToUpload = path.resolve(__dirname, "../public/images/xero-dev.png");
  +const readStream = fs.createReadStream(pathToUpload);
  +const contentType = mime.lookup(filename);
  +
  +const accountAttachmentsResponse: any = await xero.accountingApi.createAccountAttachmentByFileName(req.session.activeTenant.tenantId, accountId, filename, readStream, {
  + headers: {
  + 'Content-Type': contentType
  + }
  +});
  ```
  # Sample App
  