undefined method `accepts_nested_attributes_for'

[webdev36]

I'm using mongoid version is 5.1.x with this gem but just got this error in the rspec test.
How can I solve this issue?
undefined method accepts_nested_attributes_for' for Order:Class`

[Startouf]

You most likely forgot to include Mongoid::Document in your model ? Are you using Rails, what's your version ?

[webdev36]

Hi @Startouf , Thanks for your kind response.
I've already added the Mongoid::Document to my model, but just got error when use this method

['Customer', 'Order'].each do |model|
      origin_class = Module.const_get("::#{model}", false)
      if origin_class
        require "ccavenue/ext/#{model.downcase.gsub(/\W/,'_')}_model"
        extension = Module.const_get("Ccavenue::Ext::#{model}Model")
        origin_class.send(:include, extension)
      end
    end

occurs error when calling this method origin_class = Module.const_get("::#{model}", false)