add some docs about require/import/typing (#494)

README.md

@@ -20,6 +20,7 @@ LevelUP
   * <a href="#basic">Basic usage</a>
   * <a href="#api">API</a>
   * <a href="#promises">Promise Support</a>
+  * <a href="#import">Import with Type Definitions</a>
   * <a href="#events">Events</a>
   * <a href="#extending">Extending LevelUP</a>
   * <a href="#multiproc">Multi-process access</a>
@@ -452,6 +453,36 @@ const main = async () {
 
 --------------------------------------------------------
 
+<a name="import"></a>
+ES6 Import and Typing(for TypeScript)
+-------------------------------------
+
+We have two ways to import(require) the levelup module in the code.
+
+### 1. The old fashioned `require`
+
+```js
+var levelup = require('levelup')
+```
+
+### 2. The new ES6 `import`
+
+```js
+import levelup from 'levelup'
+```
+
+## TypeScript
+
+LevelUp ships with TypeScript `type definitions` support out-of-box. So we can use `import` with Type Defination by default.
+
+The benefits will be:
+1. [Static Type Checking](http://2ality.com/2014/10/typed-javascript.html)
+1. [IDE IntelliSense](https://code.visualstudio.com/docs/editor/intellisense)
+
+Recommended IDE: [Visual Studio Code](https://code.visualstudio.com/)
+
+--------------------------------------------------------
+
 <a name="events"></a>
 Events
 ------