Ruby on rails 未定义<；fieldname>；ActionItem的错误

我遇到以下错误：

未定义的方法“comments=”用于

代码如下：

通信\u控制器.rb

class CorrespondenceController < ApplicationController
  protect_from_forgery
  def add
    correspondence = ActionItem.new
    correspondence.event_id = params[:event_id]
    correspondence.comments = 'cccc' #gives error
    correspondence.user_id = params[:user_id] ##gives error

    if correspondence.save
      render :json => { :status => :ok}
    else
      render :json => { :status => :fail}
    end
  end
end

class Correspondence < ActiveRecord::Base
end

类对应控制器{:status=>:ok}
其他的
render:json=>{:status=>:fail}
结束
结束
结束

通信.rb

class CorrespondenceController < ApplicationController
  protect_from_forgery
  def add
    correspondence = ActionItem.new
    correspondence.event_id = params[:event_id]
    correspondence.comments = 'cccc' #gives error
    correspondence.user_id = params[:user_id] ##gives error

    if correspondence.save
      render :json => { :status => :ok}
    else
      render :json => { :status => :fail}
    end
  end
end

class Correspondence < ActiveRecord::Base
end

类对应

迁移文件

class CreateCorespondences < ActiveRecord::Migration
  def change
    create_table :correspondences do |t|
      t.integer :event_id
      t.integer :user_id
      t.text :comments

      t.timestamps
    end
  end
end

class CreateCoreRespondences

将

通信=操作项。新建
更改为
通信=通信。新建