osp_id validate

app/models/relative_memo.rb

@@ -17,6 +17,7 @@ class RelativeMemo < ActiveRecord::Base
   # validates_length_of :subject, maximum: 50
   #validates_length_of :content, maximum: 3072
   validate :cannot_reply_to_locked_topic, :on => :create
+  validates_uniqueness_of :osp_id, :scope => [:subject, :context]
 
   acts_as_tree :counter_cache => :replies_count, :order => "#{RelativeMemo.table_name}.created_at ASC"
   acts_as_attachable