implement support of many folders
fix for feature
Merge branch 'master' of https://github.com/tonkonogov/ruckusing-migrations into module-migration-dir

* 'master' of https://github.com/tonkonogov/ruckusing-migrations:
  fix for feature
  implement support of many folders
rename main/dir to default/module, check for duplicate name/path in migration_dir
Merge branch 'module-migration-dir' into module_migration

* module-migration-dir:
  rename main/dir to default/module, check for duplicate name/path in migration_dir
  fix for feature
  implement support of many folders