Mongoid:
*Embedded Associations
Mongoid allows Embedded Associations:
embeds_one / embedded_in
embeds_many / embedded_in
To add an association (lets say the User embeds_many addresses), add this to your User file:
embeds_many :addresses
and this to your Address model file:
embedded_in :user
This will embed Address in your User model, adding a addresses method to your User class.