Updating-an-App-to-Enable-Sharing.md

+Do this if you built an app before app sharing was introduced.
+
+1. [Update app to use environment variable RAILS_DATAROOT](Update-app-to-use-environment-variable-RAILS_DATAROOT)
+2. [Update gitignore](Update-gitignore)
+3. [Add app manifest](Add-app-manifest)