Bump to v3.4.0.

lodash.sum/README.md

@@ -0,0 +1,20 @@
+# lodash.sum v3.4.0
+
+The [modern build](https://github.com/lodash/lodash/wiki/Build-Differences) of [lodash’s](https://lodash.com/) `_.sum` exported as a [Node.js](http://nodejs.org/)/[io.js](https://iojs.org/) module.
+
+## Installation
+
+Using npm:
+
+```bash
+$ {sudo -H} npm i -g npm
+$ npm i --save lodash.sum
+```
+
+In Node.js/io.js:
+
+```js
+var sum = require('lodash.sum');
+```
+
+See the [documentation](https://lodash.com/docs#sum) or [package source](https://github.com/lodash/lodash/blob/3.4.0-npm-packages/lodash.sum) for more details.