Post *newPost = malloc(sizeof(Post));
        strncpy(newPost->author, author->name, MAX_NAME);
        newPost->author[MAX_NAME-1] ='\0';
        newPost->contents = contents;
        if (target->first_post == NULL) {
            newPost->next = NULL;
            target->first_post = newPost;
        } else {
            newPost->next = target->first_post;
            target->first_post = newPost;
        }
    }
new post should be inserted infront of the list