Added .ref(refName) documentation

Author: marlonbernardes

docs/README.md

@@ -82,6 +82,7 @@
     * [someWhere(predicate)](/docs/api/ReactWrapper/someWhere.md)
     * [every(selector)](/docs/api/ReactWrapper/every.md)
     * [everyWhere(selector)](/docs/api/ReactWrapper/everyWhere.md)
+    * [ref(refName)](/docs/api/ReactWrapper/ref.md)
   * [Static Rendering](/docs/api/render.md)
   * [Selectors](/docs/api/selector.md)
 * [Change Log](/CHANGELOG.md)

docs/api/ReactWrapper/ref.md

@@ -0,0 +1,31 @@
+# `.ref(refName) => Any`
+
+Returns a wrapper of the node that matches the provided reference name.
+
+
+NOTE: can only be called on a wrapper instance that is also the root instance.
+
+#### Arguments
+
+1. `refName` (`String`): The ref attribute of the node
+
+
+#### Returns
+
+`ReactWrapper`: A wrapper of the node that matches the provided reference name.
+
+
+
+#### Example
+
+
+```jsx
+const wrapper = mount(<MyComponent foo={10} />);
+expect(wrapper.prop('foo')).to.equal(10);
+```
+
+
+#### Related Methods
+
+- [`.props() => Object`](props.md)
+- [`.state([key]) => Any`](state.md)