diff --git a/app/models/token.rb b/app/models/token.rb
index 54e251a4..a5199c77 100644
--- a/app/models/token.rb
+++ b/app/models/token.rb
@@ -17,6 +17,7 @@
 
 class Token < ActiveRecord::Base
   belongs_to :user
+  validates_uniqueness_of :value
   
   @@validity_time = 1.day