Support for environment-local migrations that trigger indexing. This is similar to the local migrations for the regular `migrations` service.
Motivation
This folder is designed to contain migration files specific to a specific deployed instance of the app. These files will be ignored by git. The typical use case for this folder includes migrations containing sensitive data or those related to a re-sync of consumers. Migrations that should be applied to all instances of the app should be stored outside of this folder, but within the 'migrations-triggering-indexing' folder.