This is a demo project for mongo-scala-driver. I want to create a simple question&answer site, it has such top-level classes: 1. User 2. Question 3. Answer 4. Tag And 2 embedded classes: 1. QComment of Question 2. AComment of Answer There relations are: User - has many Question refs - has many Answer refs - has many Tag refs Question - has a User ref - has many Answer refs - embeds some comments(QComment) Answer - has a User ref - has a Question ref - ebmeds some comments(AComment) QComment - has a Question ref - embedded in Question AComment - has a Answer ref - embedded in Answer