问卷调查表增加描述列

db/migrate/20150112080435_add_description_to_polls.rb

@@ -0,0 +1,9 @@
+class AddDescriptionToPolls < ActiveRecord::Migration
+  def up
+    add_column :polls, :polls_description, :text
+  end
+
+  def down
+    remove_column :polls,:polls_description
+  end
+end