diff --git a/app/models/homework_common.rb b/app/models/homework_common.rb
index ac64b92c1..5f5808944 100644
--- a/app/models/homework_common.rb
+++ b/app/models/homework_common.rb
@@ -35,7 +35,7 @@ class HomeworkCommon < ApplicationRecord
   has_many :homework_review_results, :dependent => :destroy
 
   validates :name, length: { maximum: 60 }
-  validates :description, length: { maximum: 5000 }
+  validates :description, length: { maximum: 10000 }
   validates :reference_answer, length: { maximum: 5000 }
 
   # after_update :update_activity
diff --git a/db/migrate/20190726082937_add_is_md_for_homeworks.rb b/db/migrate/20190726082937_add_is_md_for_homeworks.rb
new file mode 100644
index 000000000..0b25dde97
--- /dev/null
+++ b/db/migrate/20190726082937_add_is_md_for_homeworks.rb
@@ -0,0 +1,12 @@
+class AddIsMdForHomeworks < ActiveRecord::Migration[5.2]
+  def change
+    # add_column :homework_commons, :is_md, :boolean, :default => true
+    # add_column :homework_banks, :is_md, :boolean, :default => true
+    #
+    #
+    # add_column :exercise_questions,:is_md, :boolean, :default => true
+    # add_column :poll_questions,:is_md, :boolean, :default => true
+    #
+    # add_column :exercise_bank_questions, :is_md, :boolean, :default => true
+  end
+end
diff --git a/db/migrate/20190726083814_migrate_course_is_md.rb b/db/migrate/20190726083814_migrate_course_is_md.rb
new file mode 100644
index 000000000..6988db14a
--- /dev/null
+++ b/db/migrate/20190726083814_migrate_course_is_md.rb
@@ -0,0 +1,14 @@
+class MigrateCourseIsMd < ActiveRecord::Migration[5.2]
+  def change
+    # HomeworkCommon.where(homework_type: [1, 3]).where("created_at < '2019-07-21 00:00:00'").update_all(is_md: false)
+    # HomeworkBank.where(homework_type: [1, 3]).where("created_at < '2019-07-21 00:00:00'").update_all(is_md: false)
+    #
+    # HomeworkCommon.where(homework_type: [1, 3]).where("created_at >= '2019-07-21 00:00:00' and homework_bank_id is not null").each do |homework|
+    #
+    # end
+    #
+    # ExerciseQuestion.where("created_at < '2019-07-21 00:00:00'").update_all(is_md: false)
+    # PollQuestion.where("created_at < '2019-07-21 00:00:00'").update_all(is_md: false)
+    # ExerciseBankQuestion.where("created_at < '2019-07-21 00:00:00'").update_all(is_md: false)
+  end
+end