Execute shells out to a `program`, passing it STDIN (if given) and any specified arguments.

NewAtlasDirMigrator returns a [AtlasDirMigrator], which is a pgtestdb.Migrator that uses the `atlas` CLI tool to perform migrations.

NewPgxTestDB will use the pgtestdb package to migrate, creates a isolated database and returns the connection string to that database..

SetupPgxPool will init a isolated test database from a connection string and a snapshot sql file.

AtlasDirMigrator is a pgtestdb.Migrator that uses the `atlas` CLI tool to perform migrations.

ExecuteFunc defines the signature for executing a command.

SnapshotMigrator loads a migration from a postgres dump file.