adds verification tries to letter code [#332]

db/migrate/20150910092713_add_letter_verification_tries_to_users.rb

@@ -0,0 +1,5 @@
+class AddLetterVerificationTriesToUsers < ActiveRecord::Migration
+  def change
+    add_column :users, :letter_verification_tries, :integer, default: 0
+  end
+end