Added guide for updates

docs/tutorial/updates.md

@@ -0,0 +1,42 @@
+# Updating Applications
+
+There are several ways to update an Electron application. The easiest and officially supported one is taking advantage of the built-in [Squirrel](https://github.com/Squirrel) framework and the [autoUpdater](../api/auto-updater.md) module that comes with it.
+
+## Deploying an Update Server
+
+To get started, you firstly need to deploy an update server (that's where the [autoUpdater](../api/auto-updater.md) module will download new updates from).
+
+Depending on your needs, you can choose from one of these:
+
+- [Hazel](https://github.com/zeit/hazel) – Pulls new releases from [GitHub Releases](https://help.github.com/articles/creating-releases/) and is **perfect for getting started**
+- [Nuts](https://github.com/GitbookIO/nuts) – Also uses [GitHub Releases](https://help.github.com/articles/creating-releases/), but caches app updates on disk
+- [electron-release-server](https://github.com/ArekSredzki/electron-release-server) – Provides you with a dashboard for handling releases
+
+## Implemeting Updates into Your App
+
+Once you've deployed your update server, continue with importing the required modules in your code (please ensure that the code below will only be executed in production - you can use [electron-is-dev](https://github.com/sindresorhus/electron-is-dev) for that):
+
+```js
+const { app, autoUpdater } = require('electron')
+```
+
+Next, put together the URL of the update server:
+
+```js
+const server = <your-deployment-url>
+const feed = `${server}/update/${process.platform}/${app.getVersion()}`
+```
+
+As the final step, tell [autoUpdater](../api/auto-updater.md) where to ask for updates:
+
+```js
+autoUpdater.setFeedURL(feed)
+```
+
+That's all. Once [built](../tutorial/application-distribution.md), your application will receive an update for each new [GitHub Release](https://help.github.com/articles/creating-releases/) that you create.
+
+## Further Steps
+
+Now that you've configured the basic update mechanism for your application, you need to ensure that the user will get notified when there's an update (this can be achieved using [events](../api/auto-updater.md#events)).
+
+Also make sure that potential errors are [being handled](../api/auto-updater.md#event-error).