Post *temp = (user_to_del->first_post)->next;
        free((user_to_del->first_post)->contents);
        free((user_to_del->first_post)->date);
        free(user_to_del->first_post);
        user_to_del->first_post = temp;
deallocate dynamically allocated memory for struct first_post and date and contents in the linked list with first struct first_post