Generates an Ecto migration to apply pending GoodAnalytics schema changes.
Usage
mix good_analytics.gen.migrationThis creates a migration file in your host application that calls
GoodAnalytics.Migration.up/0 and GoodAnalytics.Migration.down/0.
EctoEvolver tracks which versions have already been applied, so only
new versions will run.
Then run mix ecto.migrate as usual.