store ip address and current user with incoming links

make links long an readable in share dialog

db/migrate/20130426044914_allow_nulls_in_incoming_links.rb

@@ -0,0 +1,6 @@
+class AllowNullsInIncomingLinks < ActiveRecord::Migration
+  def change
+    change_column :incoming_links, :referer, :string, limit:1000, null: true
+    change_column :incoming_links, :domain, :string, limit:100, null: true
+  end
+end