[URMF] Couchbase based Persistence

[jinyoung]

Why NoSQL (couchbase) ??

1. Easy multi-tenancy support - Horizontally scalable and Schema Free
2. Web browser optimized - JSON data can be parsed by web browser directly and performantly.
3. High Performance - Memory cached and fast read
4. Easy to implement Analytic services (MR) and Full Text Search
5. Event-driven architecture - no need to care about CQRS something
6. Some NoSQL products provides pessimistic locking and ANSI SQL let you can easily migrate to them.