Mention that we don't recommend inheritance in the component doc (#487)

content/docs/reference-react-component.md

@@ -33,6 +33,8 @@ class Greeting extends React.Component {
 
 If you don't use ES6 yet, you may use the [`create-react-class`](/docs/react-api.html#createclass) module instead. Take a look at [Using React without ES6](/docs/react-without-es6.html) to learn more.
 
+Note that **we don't recommend creating your own base component classes**. Code reuse is primarily achieved through composition rather than inheritance in React. Take a look at [these common scenarios](/docs/composition-vs-inheritance.html) to get a feel for how to use composition.
+
 ### The Component Lifecycle
 
 Each component has several "lifecycle methods" that you can override to run code at particular times in the process. Methods prefixed with **`will`** are called right before something happens, and methods prefixed with **`did`** are called right after something happens.