View Source mix compile.gen_appup (Jellyfish v0.2.2)

Locate previous versions and triggers the appup files generation for hot upgrades

Copied/modified from https://github.com/bitwalker/distillery/blob/master/lib/distillery/tasks/gen.appup.ex

The generated appup will be written to rel/appups/<app>/<from>_to_<to>.appup. You may name appups anything you wish in this directory, as long as they have a .appup extension. When you build a release, the appup generator will look for missing appups in this directory structure, and scan all .appup files for matching versions. If you have multiple appup files which match the current release, then the first one encountered will take precedence, which more than likely will depend on the sort order of the names.