class Trip
  field :name, type: String

  embeds_many :destinations
  accepts_nested_attributes_for :destinations, allow_destroy: true
end

class Destination
  field :start, type: Date
  field :finish, type: Date
 
  embedded_in :trip
  belongs_to :country
end

Parameters: {"utf8"=>"✓", "authenticity_token"=>"nuQ0Tn04uqgb4GsohVMcuD7ZTSqj3DSN76UvEMUC2BU=", "trip"=>{"name"=>"My Trip to Bahamas", "destinations_attributes"=>{"0"=>{"country_id"=>"4f831e85fe75bd2c230004ee", "start"=>"2013-01-29", "finish"=>"2013-01-30", "_destroy"=>"false", "id"=>"51046b6ffe75bd4e5e000013"}, "1"=>{"country_id"=>"4f831e85fe75bd2c230004e7", "start"=>"2014-01-01", "finish"=>"2014-01-04", "_destroy"=>"false", "id"=>"51046ce3fe75bd4e5e000019"}}}, "commit"=>"Update Trip", "id"=>"my-trip-to-bahamas"}

MOPED: 127.0.0.1:27017 QUERY        database=development collection=trips selector={"$query"=>{"_slugs"=>{"$in"=>["my-trip-to-bahamas"]}, "$and"=>[{"user_id"=>"51046b6ffe75bd4e5e000012"}]}, "$orderby"=>{"start"=>1}} flags=[] limit=-1 skip=0 batch_size=nil fields=nil (0.6957ms)
  MOPED: 127.0.0.1:27017 QUERY        database=development collection=trips selector={"$query"=>{"user_id"=>"51046b6ffe75bd4e5e000012", "_id"=>"51046b6ffe75bd4e5e000011"}, "$orderby"=>{"start"=>1}} flags=[] limit=1 skip=0 batch_size=nil fields={:_id=>1} (0.6163ms)
  MOPED: 127.0.0.1:27017 UPDATE       database=development collection=trips selector={"_id"=>"51046b6ffe75bd4e5e000011"} update={"$set"=>{"destinations"=>[{"_id"=>"51046b6ffe75bd4e5e000013", "country_id"=>"4f831e85fe75bd2c230004ee", "start"=>2013-01-29 00:00:00 UTC, "finish"=>2013-01-30 00:00:00 UTC}, {"_id"=>"51046ce3fe75bd4e5e000019", "country_id"=>"4f831e85fe75bd2c230004e7", "start"=>2014-01-01 00:00:00 UTC, "finish"=>2014-01-04 00:00:00 UTC}]}} flags=[] (0.1597ms)
  MOPED: 127.0.0.1:27017 QUERY        database=development collection=trips selector={"$query"=>{"user_id"=>"51046b6ffe75bd4e5e000012", "_id"=>{"$nin"=>["51046b6ffe75bd4e5e000011"]}}, "$orderby"=>{"start"=>1}} flags=[] limit=0 skip=0 batch_size=nil fields=nil (0.6883ms)
Completed 422 Unprocessable Entity in 4040ms (Views: 0.4ms)