Defines the behaviour for array fields.
Serialize the object from the type defined in the model to a MongoDB compatible object to store.
@example Serialize the field.
field.serialize(object)
@param [ Object ] object The object to cast.
@return [ Array ] The converted object.
@since 2.1.0
If the value is not an array or nil we will raise an error, otherwise return the value.
@example Raise or return the value.
field.raise_or_return([])
@param [ Object ] value The value to check.a
@raise [ InvalidType ] If not passed an array.
@return [ Array ] The array.
[Validate]