title: I18n::Backend::ActiveRecord with scope
body: <p>I want to enable users to overwrite custom translations in the locales/YAML-files.
  I use the <code>i18n-active_record</code> gem by Sven Fuchs which works great to use translations stored in the database.</p>
  
  <p>The problem: Users should only get their own translations, not those of others.</p>
  
  <p>So I added a <code>user_id</code> column to the <code>translations</code> table. Now I have no idea how to setup a scope for <code>I18n::Backend::ActiveRecord</code>.</p>
  
  <p>My <code>locale.rb</code> (in config/initializers):</p>
  
  <pre><code>require 'i18n/backend/active_record'
  I18n.backend = I18n::Backend::ActiveRecord.new
  
  I18n::Backend::ActiveRecord.send(:include, I18n::Backend::Memoize)
  I18n::Backend::ActiveRecord.send(:include, I18n::Backend::Flatten)
  I18n::Backend::Simple.send(:include, I18n::Backend::Memoize)
  I18n::Backend::Simple.send(:include, I18n::Backend::Pluralization)
  
  I18n.backend = I18n::Backend::Chain.new(I18n.backend, I18n::Backend::Simple.new)
  </code></pre>
  
  <p>Thanks for any ideas!</p>