title: Can't set ActiveRecord attribute - stuck as Fixnum
body: <p>I set a record's timestamp attribute (<code>datetime</code> type) to <code>0</code>. I saved it (or not). I tried to set it to <code>0</code> again.</p>
  
  <pre><code>a = MyModel.last # =&gt; #&lt;MyModel id:...
  a.updated_at     # =&gt; Tue, 12 Mar 2013 01:36:17 UTC +00:00
  a.updated_at = 0 # =&gt; 0
  a.updated_at = 0
  </code></pre>
  
  <p>I got:</p>
  
  <pre><code>NoMethodError: undefined method `change' for 0:Fixnum
  </code></pre>
  
  <p>This happened even after restarting rails and reloading the record from the database (local sqlite3). Help!</p>
  
  <p>Edit: The rails console stack trace is more illuminating than the one I get from the server:</p>
  
  <pre><code>NoMethodError: undefined method `change' for 0:Fixnum
         from /Users/nolan/.rvm/gems/ruby-1.9.2-p320/gems/activerecord-3.2.11/lib/active_record/attribute_methods/time_zone_conversion.rb:69:in `round_usec'
         from /Users/nolan/.rvm/gems/ruby-1.9.2-p320/gems/activerecord-3.2.11/lib/active_record/attribute_methods/time_zone_conversion.rb:46:in `fields_updasqliteted_at='
         from (irb):23
         from /Users/nolan/.rvm/gems/ruby-1.9.2-p320/gems/railties-3.2.11/lib/rails/commands/console.rb:47:in `start'
         from /Users/nolan/.rvm/gems/ruby-1.9.2-p320/gems/railties-3.2.11/lib/rails/commands/console.rb:8:in `start'
         from /Users/nolan/.rvm/gems/ruby-1.9.2-p320/gems/railties-3.2.11/lib/rails/commands.rb:41:in `&lt;top (required)&gt;'
         from script/rails:8:in `require'
         from script/rails:8:in `&lt;main&gt;'
  </code></pre>