change varchar to text for sale_audits

db/migrate/20170403174111_create_sale_audits.rb

@@ -9,9 +9,11 @@ class CreateSaleAudits < ActiveRecord::Migration[5.1]
       t.string :action_by, :null => false
       t.string :approved_by, :null => true
       t.datetime :approved_at, :null => true
-      t.string :remark, :index => true
+      t.text :remark
       t.timestamps
     end
-    add_index :sale_audits, [:sale_id, :action, :action_at, :remark]
+
+    add_index :sale_audits, :remark, remark: 'remark', type: :fulltext
+    add_index :sale_audits, [:sale_id, :action, :action_at]
   end
 end