renamed:

* auth_users.users_id to auth_users.auth_users_id,
* auth_roles.roles_id to auth_roles.auth_roles_id,
* auth_users_roles_map.auth_users_roles_map to auth_users_roles_map.auth_users_roles_map_id

to be more consistent with the rest of the database schema; also, mediawords_find_corrupted_sequences.pl fails to run with the old column names