diff --git a/db/migrate/20150930011457_alter_user_activities_news.rb b/db/migrate/20150930011457_alter_user_activities_news.rb
index 169ac6795..f91cbb791 100644
--- a/db/migrate/20150930011457_alter_user_activities_news.rb
+++ b/db/migrate/20150930011457_alter_user_activities_news.rb
@@ -1,10 +1,10 @@
 class AlterUserActivitiesNews < ActiveRecord::Migration
   def up
     UserActivity.all.each do |activity|
-      if activity.act_type = 'News'
+      if activity.act_type == 'News'
         if activity.act
           activity.created_at = activity.act.created_on
-          activity.updated_at = activity.act.updated_on ? activity.act.updated_on : activity.act.created_on
+          activity.updated_at = activity.act.respond_to?("updated_on") ? activity.act.updated_on : activity.act.created_on
           activity.save
         else
           activity.destroy
diff --git a/db/schema.rb b/db/schema.rb
index 9da8cdd66..6edcdcc42 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -476,6 +476,13 @@ ActiveRecord::Schema.define(:version => 20150930011457) do
 
   add_index "delayed_jobs", ["priority", "run_at"], :name => "delayed_jobs_priority"
 
+  create_table "discuss_demos", :force => true do |t|
+    t.string   "title"
+    t.text     "body"
+    t.datetime "created_at", :null => false
+    t.datetime "updated_at", :null => false
+  end
+
   create_table "documents", :force => true do |t|
     t.integer  "project_id",                :default => 0,  :null => false
     t.integer  "category_id",               :default => 0,  :null => false
@@ -490,23 +497,26 @@ ActiveRecord::Schema.define(:version => 20150930011457) do
   add_index "documents", ["created_on"], :name => "index_documents_on_created_on"
   add_index "documents", ["project_id"], :name => "documents_project_id"
 
-  create_table "dts", :force => true do |t|
-    t.string   "IPLineCode"
-    t.string   "Description"
-    t.string   "Num"
-    t.string   "Variable"
-    t.string   "TraceInfo"
-    t.string   "Method"
+  create_table "dts", :primary_key => "Num", :force => true do |t|
+    t.string   "Defect",        :limit => 50
+    t.string   "Category",      :limit => 50
     t.string   "File"
-    t.string   "IPLine"
-    t.string   "Review"
-    t.string   "Category"
-    t.string   "Defect"
-    t.string   "PreConditions"
-    t.string   "StartLine"
+    t.string   "Method"
+    t.string   "Module",        :limit => 20
+    t.string   "Variable",      :limit => 50
+    t.integer  "StartLine"
+    t.integer  "IPLine"
+    t.string   "IPLineCode",    :limit => 200
+    t.string   "Judge",         :limit => 15
+    t.integer  "Review",        :limit => 1
+    t.string   "Description"
+    t.text     "PreConditions", :limit => 2147483647
+    t.text     "TraceInfo",     :limit => 2147483647
+    t.text     "Code",          :limit => 2147483647
     t.integer  "project_id"
-    t.datetime "created_at",    :null => false
-    t.datetime "updated_at",    :null => false
+    t.datetime "created_at"
+    t.datetime "updated_at"
+    t.integer  "id",                                  :null => false
   end
 
   create_table "enabled_modules", :force => true do |t|
@@ -911,7 +921,6 @@ ActiveRecord::Schema.define(:version => 20150930011457) do
     t.datetime "created_on"
     t.integer  "comments_count",               :default => 0,  :null => false
     t.integer  "course_id"
-    t.datetime "updated_on"
   end
 
   add_index "news", ["author_id"], :name => "index_news_on_author_id"