问#<Hash:0x00007fda56b4bc88>的未定义方法`read_attribute_for_serialization

EN

def show
  @movie = Movie.find_by(id: params[:id])
  render json: { data: @movie }, serializer: MovieSerializer
end

class Movie < ActiveRecord::Base
  include ActiveModel::Serialization

  belongs_to :genre
  attr_accessor :rating, :plot, :poster
end

class MovieSerializer < ActiveModel::Serializer
  attributes :genre, :id

  belongs_to :genre
  attr_accessor :rating, :plot, :poster

  def genre
    'test'
  end
end

render json: { data: @movie }, serializer: MovieSerializer
undefined method `read_attribute_for_serialization' for #<Hash:0x00007fda56b4bc88>