func Register(fns ...func(DB) error) error {
	return DefaultCollection.Register(fns...)
}
Register registers new database migration. Must be called
from file with name like "1_initialize_db.go", where:
- 1 - migration version;
- initialize_db - comment.
package migrations
var DefaultCollection = NewCollection()
func SetTableName(name string) {
	DefaultCollection.SetTableName(name)
}
func Version(db DB) (int64, error) {
	return DefaultCollection.Version(db)
}
func SetVersion(db DB, version int64) error {
	return DefaultCollection.SetVersion(db, version)
}