diff --git a/app/models/course_group.rb b/app/models/course_group.rb
index c7fc81df4..680fa6497 100644
--- a/app/models/course_group.rb
+++ b/app/models/course_group.rb
@@ -12,8 +12,7 @@ class CourseGroup < ActiveRecord::Base
   before_destroy :set_member_nil
 
   attr_accessible :name
-  validates :name, :presence => true, :length => {:maximum => 20}
-  validate :unique_name_and_course
+  validates :name, :presence => true, :length => {:maximum => 20}, :uniqueness => { :scope => :course_id}
 
 
 
@@ -22,10 +21,5 @@ class CourseGroup < ActiveRecord::Base
        self.members.update_all("course_group_id = 0")
     end
   end
-  private
-  def unique_name_and_course
-    if CourseGroup.where("name=? and course_id=?", name, course_id).first
-      errors.add(:name, :groupname_repeat)
-    end
-  end
+  
 end