Add some docs on how to push out a new release

Some context, https://gitlab.com/gitlab-org/gitter/gitter-ios-app/issues/49#note_229761124

Related to https://gitlab.com/gitlab-org/gitter/gitter-ios-app/merge_requests/6

README.md

@@ -66,6 +66,31 @@ If [aharren/LibComponentLogging-Core#24](https://github.com/aharren/LibComponent
 Originally forked from https://bitbucket.org/troupe/troupeappios
 
 
+
+## Release
+
+### Testflight (alpha/beta)
+
+Follow the instructions from https://medium.com/@dmathewwws/steps-to-put-your-app-on-testflight-and-then-the-ios-app-store-10a7996411b1.
+
+In the near future, we want to use Fastlane, https://gitlab.com/gitlab-org/gitter/gitter-ios-app/merge_requests/3
+
+ 1. Bump the `CFBundleShortVersionString` version in `Gitter/Gitter-Info.plist`
+ 1. Create `Gitter/GitterSecrets-Prod.plist` just like `Gitter/GitterSecrets-Dev.plist`
+     - Copy the secrets from https://gitlab.com/gl-gitter/secrets/blob/master/ios/prod
+     - In the Xcode navigator tab on the left, open up the `Gitter` folder, right-click on the `Supporting Files` folder, `Add files to "Gitter"...`, and select the secret plist file, https://i.imgur.com/GGJ1Uu3.png
+ 1. Change your build target to "Generic iOS Device"
+ 1. In the menu bar, to to **Product** -> **Archive**
+ 1. After the build finishes, **Distribute App** and go through the flow all the way to **Upload**
+ 1. Go to https://appstoreconnect.apple.com/WebObjects/iTunesConnect.woa/ra/ng/app/886185078/testflight?section=iosbuilds
+ 1. Wait for the app to process, then click on the build
+ 1. Add some testers and kick off the review process (same flow)
+
+### Push to production
+
+TBD
+
+
 ### Generic App Store update messages
 
 English (U.K.)