close #6, now we have a rust function update_db_with_word
and C counterpart db_update_with_word, used to give feeback to the database
close #8, added rust interface update_db_with_user_db
and C interface db_update_with_user_db, to update main database based on
user-specific data, how this user database is created/updated is let to
the discretion of the developer using this library, they can use the already
provided functiosn to create and dump a db from a CSV