implements #2658: private forum topics

db/migrate/20161024220345_add_min_level_to_forum_topics.rb

@@ -0,0 +1,5 @@
+class AddMinLevelToForumTopics < ActiveRecord::Migration
+  def change
+  	add_column :forum_topics, :min_level, :integer, :default => 0, :null => false
+  end
+end