Added Tag serializer config
Added Collection serializer config
Added Category serializer config
Merge pull request #12 from sylvaindeloux/serializer

Serializer
Fixed serialization config
Merge pull request #13 from sylvaindeloux/serializer

Fixed serialization config
Fix property name
Refactor Manager (https://github.com/sonata-project/SonataCoreBundle/commit/2391040a4d0f47cce1be2add4eb8089ad346f8ac)
Fixed fonctional test