adding docs for componentWillAppear and componentDidAppear

docs/10.1-animation.md

@@ -143,6 +143,14 @@ You can disable animating `enter` or `leave` animations if you want. For example
 
 `ReactTransitionGroup` is the basis for animations. It is accessible as `React.addons.TransitionGroup`. When children are declaratively added or removed from it (as in the example above) special lifecycle hooks are called on them.
 
+### `componentWillAppear(callback)`
+
+This is called at the same time as `componentDidMount()` for components that are initially mounted in a `TransitionGroup`. It will block other animations from occurring until `callback` is called. It is only called on the initial render of a `TransitionGroup`.
+
+### `componentDidAppear()`
+
+This is called after the `callback` function that was passed to `componentWillAppear` is called.
+
 ### `componentWillEnter(callback)`
 
 This is called at the same time as `componentDidMount()` for components added to an existing `TransitionGroup`. It will block other animations from occurring until `callback` is called. It will not be called on the initial render of a `TransitionGroup`.