Revert "Don't open MetaMask website after install"

app/scripts/background.js

@@ -41,6 +41,7 @@ const {
 const firstTimeState = Object.assign({}, rawFirstTimeState, global.METAMASK_TEST_CONFIG)
 
 const STORAGE_KEY = 'metamask-config'
+const METAMASK_DEBUG = process.env.METAMASK_DEBUG
 
 log.setDefaultLevel(process.env.METAMASK_DEBUG ? 'debug' : 'warn')
 
@@ -472,3 +473,11 @@ function openPopup () {
     }
   )
 }
+
+// On first install, open a window to MetaMask website to how-it-works.
+extension.runtime.onInstalled.addListener(function (details) {
+  if ((details.reason === 'install') && (!METAMASK_DEBUG)) {
+    extension.tabs.create({url: 'https://metamask.io/#how-it-works'})
+  }
+})
+