int make_post(const User *author, User *target, char *contents) {
        Post new_post;
        *new_post.contents = *contents;
        strcpy(new_post.author, (*author)->name);

        time_t curtime;
        time(&curtime);
        new_post.date = ctime(&curtime);

        new_post->next = target->first_post;
        target->first_post = new_post;
        return 0;
}

typedef struct post {  
    char author[MAX_NAME];  
    char *contents;  
    time_t *date;  
    struct post *next;  
} Post;  
Make a new post from 'author' to the 'target' user,
 * containing the given contents, IF the users are friends.
 *
 * Insert the new post at the *front* of the user's list of posts.
 *
 * 'contents' is a pointer to heap-allocated memory - you do not need
 * to allocate more memory to store the contents of the post.
 *
 * Return:
 *   - 0 on success
 *   - 1 if users exist but are not friends
 *   - 2 if either User pointer is NULL