Add validation for item.name, only allow [a-zA-z-_]

app/models/item.rb

@@ -14,6 +14,7 @@ class Item
   key :position, Integer, :required => true
   key :is_published, Boolean, :required => true, :default => true, :index => true
  
+  validates_format_of :name, :with => /^[a-zA-Z-_]+$/
   belongs_to :parent, :class_name => "Item", :foreign_key => :parent_id
   many :children, :class_name => "Item", :foreign_key => :parent_id