Sub-Resource data should be embedded in Resource entity or duplicated in NoSQL document?

I have a scenario similar to as depicted below,

public class Post {
    private int id;
    private int postType;
    private int score;
    private User originalPoster;
    private String title;
    private String body;
    private String tags;

}

public class Comment {
    private int id;
    private int postId;
    private String text;
    private int score;
    private User userId;
}

public class User {
    int id;
    String displayName;
    int score;
}

How do I model my MongoDb document/domain object?

My initial options are,

1) Have a separate Post and Comment collections and handle updates/retrievals hide behind my Rest Resource with possible duplicate of Comment in both Post and Comment.

2) Have a single Document Post and include everything in it and have only one Rest Resource? This will limit my url templates or need for complex data retrievals at MongoDB end.

Whether I should go with 1) or 2) or there is other approach where I can have flexibility of urltemplates and minimize the NoSQL interactions?