docs: ✏️ add documentation

Issues: testing-library#16

Author: Gpx

README.md

@@ -28,4 +28,66 @@ From
 as the user interacts with it. For example `userEvent.click(checkbox)` would
 change the state of the checkbox.
 
-The library is still a work in progress and any help is appreciated.
+**The library is still a work in progress and any help is appreciated.**
+
+## Installation
+
+With NPM:
+
+`npm install user-event --dev`
+
+With Yarn:
+
+`yarn add user-event --dev`
+
+Now simply import it in your tests:
+
+```js
+import userEvent from "user-event";
+// or
+var userEvent = require("user-event");
+```
+
+## API
+
+### `click(element)`
+
+Clicks `element`, depending on what `element` is it can have different side
+effects.
+
+```jsx
+import React from "react";
+import { render } from "react-testing-library";
+import userEvent from "user-event";
+
+const { getByText, getByTestId } = test("click", () => {
+  render(
+    <div>
+      <label htmlFor="checkbox">Check</label>
+      <input id="checkbox" data-testid="checkbox" type="checkbox" />
+    </div>
+  );
+});
+
+userEvent.click(getByText("Check"));
+expect(getByTestId("checkbox")).toHaveAttribute("checked", true);
+```
+
+### `type(element, text, [options])`
+
+Writes `text` inside an `<input>` or a `<textarea>`. `options` accepts one
+argument `allAtOnce` which is `false` by default. If it's set to `true` it will
+write `text` at once rather than one character at the time.
+
+```jsx
+import React from "react";
+import { render } from "react-testing-library";
+import userEvent from "user-event";
+
+const { getByText } = test("click", () => {
+  render(<textarea data-testid="email" />);
+});
+
+userEvent.type(getByTestId("email"), "Hello, World!");
+expect(getByTestId("email")).toHaveAttribute("value", "Hello, World!");
+```