Fix first migration

Author: root

db/migrate/20130910195931_add_columns_to_repository_git_notification.rb

@@ -1,13 +1,8 @@
 class AddColumnsToRepositoryGitNotification < ActiveRecord::Migration
 
   def self.up
-    unless RepositoryGitNotification.column_names.include? 'prefix'
-      add_column :repository_git_notifications, :prefix, :string
-    end
-
-    unless RepositoryGitNotification.column_names.include? 'sender_address'
-      add_column :repository_git_notifications, :sender_address, :string
-    end
+    add_column :repository_git_notifications, :prefix, :string
+    add_column :repository_git_notifications, :sender_address, :string
   end
 
   def self.down