Add rss2_id.

app/models/course.rb

@@ -10,6 +10,7 @@ class Course
 	field :year, type: Integer
     field :student_ids, type: Array, default: []
     field :course_code, type: String, default: ""
+    field :rss2_id
 	has_many :course_syllabus_files, :dependent => :destroy, :autosave => true
 	has_many :course_progress_files, :dependent => :destroy, :autosave => true
 	has_many :course_activity_files, :dependent => :destroy, :autosave => true