Here is a way to restore from a file located on the host machine:
docker exec -i container_name pg_restore -U postgres_user -v -d database_name < /dir_backup_outside_container/file_name.tar
Here is a way to restore from a file located on the host machine:
docker exec -i container_name pg_restore -U postgres_user -v -d database_name < /dir_backup_outside_container/file_name.tar