Instructor :: CoursesController＃create中的NoMethodError

Question

当我尝试为新课程添加图像时，它弹出错误消息undefined method 'courses' for <User:0x00007fb62c5cf5f0>。您能否让我知道缺少的部分。请检查我在CourseController#create上的代码，非常感谢。

  

问题：Instructor :: CoursesController＃create

中的NoMethodError

class Instructor::CoursesController < ApplicationController
    before_action :authenticate_user!

    def create
        @course = current_user.courses.create(course_params)
        if @course.valid?
            redirect_to instructor_course_path(@course)
        else
            render :new, status: :unprocessable_entity
        end
    end

private

    def course_params
        params.require(:course).permit(:title, :description, :cost, :image) 
    end
end