Summary:**Motivation:** I don't like storing credentials in config files and a safer solution is to store them in the Keychain Access app.
Therefore I added a link that describes how one may go about to store the passwords in the Keychain Access app in OSX instead.
Found a [stackoverflow post](http://stackoverflow.com/a/24480579/1836121) but it wasn't very detailed so I decided to write it up myself. I understand if you have some policy against external links to blogs and I guess we could link to the stackoverflow explanation then instead.
Closes https://github.com/facebook/react-native/pull/7089
Differential Revision: D3207215
fb-gh-sync-id: 8011b55efe41ec6d54ad665e0e6a79cb9d806779
fbshipit-source-id: 8011b55efe41ec6d54ad665e0e6a79cb9d806779
Summary:From the documentation I thought I only had to sign an application if I intended to publish it to the Play Store. Turns out this is not true. Signing is still required if you want to install the APK on any device at all. Unsigned APK's are for simulators only.
Closes https://github.com/facebook/react-native/pull/6795
Differential Revision: D3133747
fb-gh-sync-id: ae91111cb20984ebe8ac2443971b373a3f4c848e
fbshipit-source-id: ae91111cb20984ebe8ac2443971b373a3f4c848e