added validation in adimage

app/models/ad_image.rb

@@ -1,3 +1,5 @@
+require 'uri'
+
 class AdImage
   include Mongoid::Document
   include Mongoid::Timestamps
@@ -13,6 +15,16 @@ class AdImage
 
   belongs_to :banner
 
-  validates :file, :presence => true
+  before_validation :add_http
+  validates :file, presence: true
+  validates :out_link, format: { with: URI::regexp(%w(http https)) }, allow_blank: true
+  validates :title, presence: true
 
+  protected
+
+  def add_http
+    unless self.out_link.blank? || self.out_link[/^http:\/\//] || self.out_link[/^https:\/\//]
+      self.out_link = 'http://' + self.out_link
+    end
+  end
 end