added config section for testcafe (#268)

Author: benmonro

docs/testcafe-testing-library/intro.md

@@ -32,7 +32,7 @@ fixture`selectors`.beforeEach(addTestcafeTestingLibrary)
 ```
 
 ### for v3.x+ (requires testcafe 1.4.0 or greater)
-`addTestcafeTestingLibrary` was removed in 3.x, instead you can now inject clientScripts as of testcafe 1.4.0.  For now, the path has to be used, but this will hopefully be changed to a module soon (pending a change to testcafe to support `umd:main` in package.json.
+`addTestcafeTestingLibrary` was removed in 3.x, instead you can now [inject clientScripts][inject] as of testcafe 1.4.0.  For now, the path has to be used, but this will hopefully be changed to a module soon (pending a change to testcafe to support `umd:main` in package.json.
 
 ```json
   "clientScripts": [
@@ -68,6 +68,59 @@ test('getByLabelText', async t => {
 })
 ```
 
+## Configure
+You can customize the testIdAttribute using the [configure function of dom-testing-librarty][config] in a few different ways:
+
+### Once in a single page load:
+```javascript
+import { configureOnce, getByTestId } from '@testing-library/testcafe';
+
+test('can be configured once in a single page load', async t => {
+    await configureOnce({ testIdAttribute: 'data-other-test-id' });
+    await t.click(getByTestId('other-id'));
+})
+```
+
+### For every test & page load in a fixture:
+```javascript
+import { configure, getByTestId, getByText } from '@testing-library/testcafe';
+
+fixture`configure`.clientScripts(configure({ testIdAttribute: 'data-automation-id' }))
+    .page`http://localhost:13370`
+
+
+test('supports alternative testIdAttribute', async t => {
+    await t
+        .click(getByTestId('image-with-random-alt-tag'))
+})
+
+test('still works after browser page load and reload', async t => {
+    await t.click(getByText('Go to Page 2'));
+
+    await t.eval(() => location.reload(true));
+
+    await t.click(getByTestId('page2-thing'))
+        .expect(getByText('second page').exists).ok()
+})
+
+```
+
+### Globally for all fixtures, tests and page loads by [injecting clientScripts][inject]
+>Note: the dom-testing-library umd must come before your configure script
+
+.testcaferc.json
+```json
+  "clientScripts": [
+    "./node_modules/@testing-library/dom/dist/@testing-library/dom.umd.js" 
+    "./path/to/my-app-testcafe.config.js" 
+  ]
+```
+
+./path/to/my-app-testcafe.config.js
+```javascript
+window.TestingLibraryDom.configure({ testIdAttribute: 'data-automation-id' });
+```
+
 ## Containers
 
 By default the selectors come pre-bound to `document.body`, so no need to
@@ -109,5 +162,6 @@ test('works with nested selector from "All" query with index', async t => {
   await t.expect(nested.getByText('Button Text').exists).ok();
 });
 ```
-
+[config]: https://testing-library.com/docs/dom-testing-library/api-configuration
 [gh]: https://github.com/benmonro/testcafe-testing-library
+[inject]:https://devexpress.github.io/testcafe/documentation/using-testcafe/common-concepts/inject-scripts-into-tested-pages.html#add-client-scripts-to-all-tests