create_field.rb

def create_field(field, field_attributes)
	# Multiple values
	if is_a_kind_of_collection? field_attributes
	  self.contact.send "#{field}=", parse_multiple_values(field_attributes, field)
	else
          parse_single_values field_attributes, field
	end
end

private

def is_a_kind_of_collection? field_attributes
	field_attributes.is_a?Array or field_attributes.is_a?ActiveRecord::Associations::CollectionProxy
end

def parse_multiple_values field_attributes, field
  multiple_values = [] 
	field_attributes.each do |atr|
		atr = atr.attributes if field_attributes.is_a?ActiveRecord::Associations::CollectionProxy
		atr.reject! {|k,v| k.eql?"id" }
		atr.merge!({ :user_id => self.address_book.user.id })
		multiple_values << field.singularize.camelize.constantize.new(atr)
	end
	multiple_values
end

def parse_single_values field_attributes, field
  # Single values
  field_attributes.reject! {|k,v| k.eql?"id" }
  field_attributes.merge!({ :user_id => self.address_book.user.id })
  self.contact.send "#{field}=", field.camelize.constantize.new(field_attributes)
end